Thèse Dirigée Par

Taniel Danelian

Araik Grigoryan

Catherine Crônier

Crasquin Sylvie

Rapporteur

Invité Cronier

M.S Abrahamyan

Novyye Vidy Brakhiopod Iz Verkhnego

1974, Opisanie fauny, Devonskaya sistema, Tip Brachiopoda, Brakhiopody In Akopian

Armyanskoy Ssr

: Yerevan

Akademiya Nauk

M.S Arakelyan Abrahamyan

Malyy Kavkaz

Yuzhnoe Zakavkaz'ya)

In Rzhonsnitskaya

Kavkazskaya Geosinklinal'naya Oblast I Predkavkaz'e, In Nalivkin

Stratigrafiya Sssr

Devonskaya

Granitsa Devona

Nizhnego Karbona

Stratigrafiya Karbona

R E Alekseeva

Brachiopodes du Dévonien supérieur et séquences sédimentaires d'Arménie; biodiversité, stratigraphie et paléobiogéographie

Keywords: Brachiopoda, Rhynchonellida, Atrypida, Athyrida, Spiriferida, Frasnian, Famennian, Kellwasser Biocrisis, Gondwana, Lesser Caucasus, South Armenian Block, Armenia, Nakhichevan Brachiopodes, Rhynchonellida, Atrypida, Athyrida, Spiriferida, Frasnien, Famennien, Crise biologique de Kellwasser, Gondwana, Petit Caucase, Bloc sud arménien, Arménie, Nakhichevan 1858, Vergleichende geologische Grundzüge der Kaukasischen, Armenischen und Nordpersischen Gebirge: Prodromus einer Geologie der Kaukasischen Länder:

The Upper Devonian carbonate-siliciclastic sedimentary sequences and brachiopods from three distinct sections (Ertych, Djravank and Noravank) of Central Armenia are here examined.

Paleoenvironmental interpretation is performed based on bio-and lithofacies to reconstruct the depositional environments in which the sedimentary sequences were accumulated. Moreover, the studied sections are correlated lithostratigraphically, as well as biostratigraphically by focusing on Armenian Block (SAB) into Afghanistan and Pamir, although there are also many endemic elements. Finally, the paleobiogeographic significance of the four newly defined genera is discussed, including the re-assignment to them of several other Famennian species known previously from Nakhichevan, Pamir (Tajikistan), Central Kazakhstan and the East European Platform.

their brachiopod assemblages. Twenty-six brachiopod species are described on the basis of recently collected material from the Frasnian-Famennian (F-F) succession. Four new brachiopod genera (Aramazdospirifer, Angustisulcispirifer, Pentagonospirifer and Tornatospirifer) and five new species (Ripidiorhynchus djravankensis, Cyrtospirifer pseudoasiaticus, Pseudocyrtiopsis areniensis, Pentagonaspirifer abrahamyanae and Angustisulcispirifer arakelyani) are introduced.

All brachiopod species are examined according to modern taxonomic concepts and illustrated both externally and internally, with the exception of some rare species. The intraspecific morphological variability of the described species is documented quantitatively. The previously suggested biostratigraphic scheme for brachiopods of the F-F interval of the Lesser Caucasus (Armenia and Nakhichevan) is revised. More particularly, the Ripidiorhynchus gnishikensis-Angustisulcispirifer arakelyani brachiopod Zone, of Frasnian age, characterizes the peloidal grainstones of the Interval 1 that accumulated as a highstand system tract, while the lower Famennian Aramazdospirifer orbelianus-Tornatospirifer armenicus Zone is found in the packstones/grainstones of the Interval 4, which was deposited during a transgressive event. The present study also documents the diversity of brachiopods reported from the Frasnian-lower Famennian sequences of the Lesser Caucasus; the synthesis of all previous and current data suggests that a major change in diversity took place amongst rhynchonellides, atrypides and spiriferides. From a paleobiogeographic viewpoint, the studied fauna clearly shares affinities with contemporaneous brachiopods known from other parts of the north-Gondwanan margin, especially from those areas that extend eastwards of the South

Introduction

The Late Devonian (383-359 Ma) marked a critical period in the history of biodiversity, as it coincided with a number of significant geo-and bio-events of which the most astounding is the Frasnian-Famennian (F-F) biocrisis, considered as one of the "Big Five" mass extinctions events known from the Phanerozoic (see [START_REF] Mcghee | The Late Devonian mass extinction. The Frasnian/Famennian Crisis[END_REF][START_REF] Mcghee | When the Invasion of Land Failed: the Legacy of the Devonian Extinctions[END_REF][START_REF] Walliser | Global events in the Devonian and Carboniferou[END_REF][START_REF] Baliński | Frasnian-Famennian brachiopod extinction and recovery in southern Poland[END_REF][START_REF] Racki | Late Devonian biotic crisis: ecological, depositional and geochemical records: Palaeogeographi Palaeoclimatologi[END_REF]. It is also referred to as the two-step "Kellwasser Event" (e.g., [START_REF] Schindler | Event-stratigraphic markers within the Kellwasser Crisis near the Frasnian/Famennian boundary (Upper Devonian) in Germany[END_REF][START_REF] Gereke | The "Time-Specific Facies and biological crises-the Kellwasser Event interval near the Frasnian/Famennian boundary (Late Devonian)[END_REF]; it is subdivided into the Lower and Upper Kellwasser Event (LKE and UKE, respectively); this separation is based on its appearance in Germany and in other study localities, where it forms two distinct black shale layers (referred to as the Lower and Upper Kellwasser Horizons) [START_REF] Buggisch | The global Frasnian-Famennian Kellwasser event[END_REF][START_REF] Riquier | The Late Frasnian Kellwasser horizons of the Harz Mountains (Germany): two oxygen deficient periods resulting from different mechanisms[END_REF]Schindler, 1990a;Schindler, 1990b).

The LKE is found within the Lower gigas/Palmatolepis rhenana conodont Zone, whereas the UKE is found at the top of the Palmatolepis linguiformis conodont Zone [START_REF] Becker | The Devonian period[END_REF][START_REF] Klapper | Definition of the Frasnian-Famennian stage boundary: Episodes[END_REF]. The UKE marks a global biotic event corresponding to a major ecosystem perturbation at the F-F boundary. Most notably, it resulted in the decimation of the low-latitude metazoan reef systems [START_REF] Sorauf | Late Devonian rugose corals and the Frasnian-Famennian crisis[END_REF]Copper, 2002), as well as benthic (e.g. trilobites, ostracods and brachiopods) and nektonic (e.g. ammonoids, tentaculites and conodonts) marine communities [START_REF] Mcghee | The Late Devonian mass extinction. The Frasnian/Famennian Crisis[END_REF][START_REF] Walliser | Global events in the Devonian and Carboniferou[END_REF][START_REF] Ma | The Late Devonian Frasnian-Famennian event in South China-patterns and causes of extinctions, sea level changes, and isotope variations[END_REF]. Although most paleontologists agree that the marine biosphere experienced severe losses at the F-F boundary, a consensus still remains elusive regarding the mechanism (extinction versus lack of origination) and severity of the crisis (compared to other times of biotic crisis). One of the main challenges in attaining this consensus is a parallel lack of consensus about the cause of the extinction/depletion. Most notably as noted by [START_REF] Racki | Toward understanding Late Devonian global events: few answers, many questions[END_REF], [START_REF] Stigall | Speciation collapse and invasive species dynamics during the Late Devonian "Mass Extinction[END_REF] and [START_REF] Stanley | Estimates of the magnitudes of major marine mass extinctions in earth history[END_REF] the main cause of this biotic crisis and the resulting disruption of the epeiric carbonate factory appears to be not the elevated extinction rates, but reduced speciation rates and, therefore this event should be considered as representing a massive diversity depletion event and not as a mass extinction event; thus they suggest it to be defined as the F-F Biodiversity Crisis. It is also worth to emphasize that this biocrisis affected mostly shallow water marine ecosystems, resulting in a permanent decline of shallow water coral/stromatoporoid reef communities and the elimination of some brachiopod clades related to tropical and subtropical settings [START_REF] Mcghee | The Late Devonian mass extinction. The Frasnian/Famennian Crisis[END_REF][START_REF] Racki | Frasnian-Famennian biotic crisis: undervalued tectonic control?[END_REF][START_REF] Huang | The influence of the Late Devonian Kellwasser events on deep-water ecosystems: evidence from palaeontological and geochemical records from South China[END_REF].

The Upper Devonian sequences of Central Armenia and Nakhichevan (Fig. 1) are represented by shallow water, mixed carbonate-siliclastic deposits; they are remarkable in terms of their completeness and richness in fossil remains (Abrahamyan 1957(Abrahamyan , 1964(Abrahamyan , 1974;;Arakelyan 1964;Alekseeva et al., 2018a, b). They have attracted the interest of pioneer geologists such as the famous German geologist Hermann Abich, who first described in 1858 Devonian outcrops and a new spiriferide species ('Spirifer' orbelianus) from Armenia (Serobyan et al., in press). In this country, Upper Devonian-Lower Carboniferous brachiopods were systematically studied by Abrahamyan during the years 1949 to 1974. One of her most important publications dates back to 1957, in which she described and illustrated 36 brachiopod species (including eight new ones) from the Famennian-Tournaisian interval. The latter brachiopods were partly revised by Abrahamyan (1974) in addition to newly studied Frasnian species. However, despite the extensive taxonomic studies led by Abrahamyan (1957Abrahamyan ( , 1974) ) and more recently by Alekseeva et al. (2018a, b), who mainly focused on brachiopods from Nakhichevan (Fig. 1), brachiopods from this area still remain largely undocumented from a taxonomic and biostratigraphic point of view. This is especially true for the Upper Devonian brachiopods, many of which were described without any examination of their most fundamental features such as their internal morphology, their pseudodeltidium and their type of micro-ornament, all of which are significant for their supraspecific classification. Re-investigation of this fauna is crucial to better understand Late Devonian changes in brachiopod diversity and their paleobiogeographic distribution. Thus, in order to understand the changes in brachiopod biodiversity during the critical Frasnian-Famennian transitional interval, the prime objective of my study has been to adress this discusses in detail the taxonomy of one of the most biostratigraphically important species of the lower Famennian in the Lesser Caucasus, Aramazdospirifer orbelianus (Abich, 1858), while at the same time introduced Aramazdospirifer as a new genus.

Chapter 5 is subdivided into five parts. The Subchapter 5.1 presents the stratigraphic distribution of early-middle Frasnian and early Famennian brachiopods in the intervals 1 and 4 in the three main stratigraphic sections, while the Subchapter 5.2 outlines a synthesis of data on the brachiopod biostratigraphy in the Lesser Caucasus and defines two new brachiopod biozones. The Subchapter 5.3 outlines the nature of early-middle Frasnian to early Famennian brachiopod biostratigraphic record and the changes in diversity throughout this interval, whereas the Subchapter 5.4 describes the paleobiogeographic distribution of the brachiopods found in the three sections studied, and finally the Subchapter 5.5 summarizes the occurrences of epibionts including cornulitids and Hederella observed in the early Famennian cyrtospiriferids.

Chapter 1

Geological, stratigraphic and paleogeographic setting conodont biozonation, based on the conodont study of Aristov (1994) (Fig. 3) carried out in Nakhichevan. In addition to these studies, [START_REF] Grechishnikova | K biostratigrafii srednego Devona Zakavkaz'ya: Byulleten' Moskovskogo Obshchestva Ispytateley Prirody[END_REF]Grechishnikova et al. ( , 1982Grechishnikova et al. ( , 1983)), [START_REF] Grechishnikova | The Famennian-Lower Carboniferous Reference Section Geran-Kalasi (Nakhichevan Autonomous Region, Azerbaijan)[END_REF] also contributed to the systematic paleontology and biostratigraphy of Middle Devonian-Lower Carboniferous brachiopods of the Lesser Caucasus, mainly focusing on sections situated in Nakhichevan (Fig. 1); the latter studies were more recently updated by Grechishnikova in Alekseeva et al. (2018a). However, these studies not only Stampfli et al., 2002).

complement each other, but they sometimes cause confusion, which is especially true for the Givetian-Frasnian and Frasnian-Famennian intervals. More particularly, across the Givetian-Frasnian boundary, Aristov (1994) recognized two conodont zones: Ancyrodella binodosa and A.

rotunbiloba. The author further specified that the binodosa Zone corresponds to the lower part of Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis brachiopod Zone, whereas the rotunbiloba Zone is coeaval to the upper part of Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis brachiopod Zone. He placed the Givetian-Frasnian boundary within the Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone. However, Rzhonsnitskaya and Mamedov (2000) raised the lower boundary of the latter brachiopod zone to the lower Frasnian. Afterwards, Alekseeva et al. (2018a) considered this brachiopod zone to be late Frasnian in age without giving any further evidence. It is certain that this assumption must be re-considered after a thorough study of conodonts, but before, it is reasonable to suppose that the age of this biozone is likely to be covering the lower-middle (lower part) Frasnian interval. Regarding to the lower Famennian, Abrahamyan (1957) and [START_REF] Grechishnikova | K biostratigrafii srednego Devona Zakavkaz'ya: Byulleten' Moskovskogo Obshchestva Ispytateley Prirody[END_REF] recognized only one brachiopod zone within this substage of the Lesser Caucasus, namely the Cyrtospirifer orbelianus. Whereas, Rzhonsnitskaya and Mamedov (2000) established two biozones: the lowest Famennian Mesoplica meisteri-Cyrtospirifer asiaticus and the lower Famennian Cyrtiopsis orbelianus-C. armenicus. [START_REF] Ginter | Chondrichthyan microfossils from the Famennian and Tournaisian of Armenia[END_REF], Caucasus, including the regional stages established by Arakelyan (1964) and brachiopod biozones of Abrahamyan (1957) in Central Armenia and of [START_REF] Grechishnikova | K biostratigrafii srednego Devona Zakavkaz'ya: Byulleten' Moskovskogo Obshchestva Ispytateley Prirody[END_REF] and Rzhonsnitskaya and Mamedov (2000) in

Nakhichevan. It also includes the regional conodont zonation established by Aristov (1994) in Nakhichevan and the standard conodont zones of [START_REF] Ziegler | The Late Devonian standard conodont zonation[END_REF].

described chondrichthyan remains from Armenia, some of which were recovered from the F-F interval of the Ertych and Noravank sections. It is worth emphasizing that they followed the biostratigraphic scheme of Rzhonsnitskaya and Mamedov (2000). Besides chondrichthyans, [START_REF] Ginter | Chondrichthyan microfossils from the Famennian and Tournaisian of Armenia[END_REF] reported conodonts above the layer of algal limestone (=oncolitic grainstone in the present study; Nv17/4) of the Noravank section, among which, some elements indicated the lower Famennian crepida Zone (see [START_REF] Ginter | Chondrichthyan microfossils from the Famennian and Tournaisian of Armenia[END_REF]text-fig. 4). Alekseeva et al. (2018a, b) followed the biostratigraphic scheme of [START_REF] Grechishnikova | K biostratigrafii srednego Devona Zakavkaz'ya: Byulleten' Moskovskogo Obshchestva Ispytateley Prirody[END_REF] and considered that the lower Famennian of the Lesser Caucasus is represented by only one brachiopod zone, but re-named it the Mesoplica meisteri-Cyrtospirifer asiaticus Zone. Finally, [START_REF] Grigoryan | A Famennian (Late Devonian) conodont assemblage from brachiopod-rich limestones of the Djravank section (southern Armenia)[END_REF] described a conodont assemblage from the upper part of the Djravank section suggesting an early Famennian age.

Chapter 2

Material and methods

The examined material was collected from the Frasnian-lower Famennian interval of Ertych, Djravank and Noravank sections (Fig. 1) during several field seasons organized in 2017-2020.

Although, during 2017-2020, I visited also several other outcrops, the current study is focused on these three sections only as they comprise well-exposed and highly fossiliferous sedimentary sequences and, thus, can provide valuable insights into events that occurred during the Late Devonian. The sections consist of shallow water carbonate-siliciclastic sediments. The limestone classification adopted herein follows [START_REF] Dunham | Classification of carbonate Rocks according to depositional texture[END_REF], which divides carbonate rocks based on their texture and mud content, and [START_REF] Dott | Greywacke and Matrix-What Approach to Immature Sandstone Classification?[END_REF] for sandstone classification. The latter is a widely used classification of sandstones which divides them on the basis of their percentage in mud matrix and then subdivdes them into types based on their grain composition.

Macrofossils (predominantly brachiopods) were collected bed-by-bed from marly/sandy limestones and shales by splitting them out of the rock. In total 1888 articulated brachiopod shells and 325 dissociated valves were collected, the main part of which is derived from a soft, weathered surface that provided well-preserved, nearly sediment-free specimens. The material sampled by our care in the field was complemented with specimens that were collected during the 1940s to 1980s by Abrahamyan and Arakelyan, both from Armenia and Nakhichevan.

The internal structure of the newly collected articulated specimens was investigated by using the standard technique of serial sections and acetate peels. The latter were assembled between microscope slides and photographed under a binocular microscope Olympus SZX 12. Afterwards, the photographs were transferred to CorelDRAW X7 software and internal details were drawn using a digital drawing tablet. Furthermore, in order to capture the fine details of the internal structure, the ground specimens were photographed directly under a Canon EOS 700D camera that was attached on a Zeiss SteREO Discovery V20 Microscope. All ground specimens were selected among recently collected material as historical specimens cannot be sectioned; thus, the latter have been used only for measurements. Statistical analysis, i.e., ANCOVA (test for comparison of several models of simple linear regression) was applied in order to determine if the regression line slopes of our four samples are significantly different. Statistical analysis was performed under the free PAST 3 software. Almost complete articulated specimens were coated with magnesium oxide before being photographed with a Canon EOS 700D camera. Specimens selected for scanning electron microscopy were coated with gold and a ZEISS EVO Scanning Electron Microscope was used to image micro-ornamentation. Afterwards, in order to enhance contrast and brightness, all images were further processed using Adobe Photoshop CS6. Specimens selected for scanning electron microscopy and studied at the Royal Belgian Institute were observed using a low vacuum SEM, an ESEM FEI Quanta 200, but not coated with gold. Specimens cited in Brice (1967) are stored at the Laboratoire de Paléontologie de la Faculté Libre des Sciences des Lille (collections De Lapparent and Brice). The material studied by Erlanger (1993) is housed at the Borissiak Paleontological Institute of the Russian Academy of Sciences, Moscow and is catalogued under the prefix PIN and collection no. 3744. The material examined by [START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF] is curated at the Vernadsky State Geological Museum, Moscow (VSGM) and is catalogued under the prefix VI and collection no. 223.

Chapter 3

The studied sections: lithostratigraphy, sequence stratigraphy and paleoenvironmental interpretation

The Ertych section

The section shows Frasnian-lower Famennian sequences situated at the southern bank of the Arpa river (ca. 8.5 km east of Areni), near the ruins of Ertych village. The base of this section, here referred to as Interval 1, mainly consists of limestone layers with a total thickness of ca. 13 m (Figs.

4.1-4.2). These limestones are nodular at the base and contain abundant brachiopod fauna, whereas in the upper part of this interval, they become well-bedded with scarce brachiopods. These grainsupported carbonate rocks (Er19/1/1, Er19/1/3, Er19/1/4; Fig. 7.1-7.6) constituting the Interval 1 are defined as peloidal bioclastic grainstones and include different fragments of brachiopod shells (e.g., Fig. 7.1, 7.4), dasycladacean algae (Fig. 7.2), gastropods (Fig. 7.3), crinoids (Fig. 7.5) and sea urchins (Fig. 7.6). In thin section, the layer Er19/1/3 contains iron dolomite (Fig. 7.4). The Interval 1 yielded abundant brachiopod fauna; a few hundred specimens were recovered from this interval.

The base of the overlying Interval 2 corresponds to 7 m of black shales (Figs. 4.3) followed upwards by 2 m thick calcareous sandstones (quartz-wacke) (Er19/5; Figs. 4.3,) that contain poorly preserved rhynchonellide brachiopods and fish bones (Fig. 8.2). The total thickness of Interval 2 is ca. 35 m; it is chiefly composed of alternations of bioturbated sandstones (quartzwacke) and black shales ). The overlying Interval 3 is primarily composed of coarse grained siliciclastic rocks and a few layers of shale. More particularly, its base is represented by sandstones which appear to be quite mature and representing facies that are intermediate between quartzite and sandstone (Fig. 8.3), whereas its middle part is constituted of quartzites and two layers of shales (Figs. 5.1); those shale layers are very rich in macro-plant remains (Fig. 5.3). The upper part of Interval 3 includes a few layers of sandstones, some of which are bioturbated (unbranched vertical narrow burrows are observed, resulting from the reworking of sediments by some organisms) and contain calcareous cement as well as many fish bones (e.g., Er19/98; Fig. 8.7-8.8), and shales; these sandstone layers are characterized as quartz-wacke. It is worth noting that the grains of the sandstones are irregularly shaped and their sphericity is quite low; thus, the grains constituting these sandstones are poorly sorted. No brachiopod specimen was recovered from this interval. The overlying Interval 4 is distinguished by the interbedding of different types of carbonate rocks. More particularly, the base of this interval consists of well-bedded and recrystallized limestone layers described as grainstone, which are covered by ca. 50 cm-thick, clearly distinct oncolitic grainstone with peloids ). The latter is overlain by tentaculite packstone layers (Er19/105, Fig. 9.1-9.3; Er19/108, 9.4-9.5), which, in addition to tentaculites, also include different fragments of brachiopods, bivalves, bryozoans, trilobites, fish bones and lithoclasts. These packstone layers appear to represent storm deposits as they are mostly composed of poorly sorted and broken fragments of animals, living at different depths. The packstone layers cropping out above, such as Er19/113 (9.6), Er19/119 (9.7) and Er19/124 (9.8) differ from the latter by possessing a large amount of fine and poorly sorted quartz grains. This interval of packstones is overlain by bioclastic grainstone layers (e.g., Er19/127, Er19/133, Er19/143) that probably correspond to storm deposits as they are composed of displaced and broken fossils such as brachiopods, trilobites (10.1), fish bones (10.2), dasycladacean algae and ostracods (10.5-10.6), which are usually encountered at different depths, and some of them also include quartz grains and peloides (e.g., 10.3-10.4) transported from a shallower environment. The overlying Er19/176 constitutes a coquina-bed (packstone facies) with peloides, fragments of tentaculites, brachiopod spines (10.7) and ostracods (10.8), whereas, the ensuing layer Er19/192 is identified as peloidal grainstone with crinoids (quite well sorted). The interval ends with relatively well-sorted and finegrained quartzite and sandstone (quartz-wacke) layers (Fig. 11. 2-11.4). The grainstone/packstone layers of Interval 4, which crop out above the oncolitic grainstone yielding abundant brachiopods; a few hundred specimens were collected that are dominated by spiriferides and rhynchonellides.

The Djravank section

The section displays Frasnian to lower Famennian sequences that crop out along a mountain path (Fig. 12.1) that starts from the ruins of the Ertych village and leads to a tiny church hidden in the mountains, at the locality known as Djravank (Fig. 1). The section is exposed ca. 500 meters to the 4). Marly and sandy nodular limestones cropping out at the top of Interval 4 that lithologically corresponds to the Ertych Regional Stage of Arakelyan (1964) and bearing brachiopod fauna of the orbelianus Zone of Abrahamyan (1957). In addition to peloides, these limestone layers also contain ostracods (Fig. 15.1), brachiopod spines (Fig. 15. 2),bryozoans (Figs. 15.2,15.5), fragments of cyanobacterial mats (Fig. 15.4) and dasycladacean algae (Fig. 15.6). They consist of displaced body fossils and display strong bioturbation (e.g., 15.5-15.6). These bioturbaion patterns seem to be open tubes produced by animals burrowing in a stable, stiff substrate, subsequently filled with sediment transported by storm-generated currents [START_REF] Wanless | Pro duction of subtidal and surficial tempestites by Hurricane Kate, Caicos Platform[END_REF]. Thus, they are here defined as peloidal bioclastic grainstones and considered to be storm deposition (tempestite). This massive graintone is interrupted by a distinct black shale layer (Fig. 12.3) below which, the grainstones are dominated by rhynchonellides, atrypides and productides, whereas the limestones cropping out above this layer contain no atrypide brachiopods. It is also important to highlight here that this black shale layer is rich in rhynchonellide brachiopods which confirms the viewpoints of [START_REF] Racki | Evolution of the bank to reef complex in the Devonian of the Holy Cross Mountains[END_REF], who aptly noted that the rhynchonellides were well-adapted to Late Devonian hypoxic habitats. Above the black shale layer, the limestones become dominated by spiriferides. Several hundred brachiopod specimens are taken from the Interval 1 to describe the brachiopod assemblage. The Interval 1 is overlain by intercalations of sandstones and shales, which in turn are covered by massive quartzites.

Although this part of the section is partly covered by huge blocks of Eocene rocks, we could observe from place to place rocks resembling the facies of Intervals 2 and 3. The top of this section, which is termed Interval 4, is distinguished by the interbedding of different types of carbonate rocks. More particularly, the base (Dj19/5; Figs. 13.1,) represents a coquina-bed facies with fragments of stromatoporoids and cyanobacteria, which probably come from lagoonal and reefal environments, ostracods (Fig. 16.3) and a large bryozoan (Fig. 16.4). This externally very fragile layer is highly rich in rhynchonellide brachiopods (Ripidiorhynchus djravankensis n. sp.).

Stratigraphically above, there is a change in facies that is observable in the field due to the resistance of the rocks (Fig. 13.1-13.2). The first bioturbated wackestone facies is observed within the layer Dj19/4 (Fig. 16.5-16.6), which clearly differs from the Dj19/5 and other layers outcropping below by being mud-supported and including a huge numbers codiacean algae (Umbella). These limestone layers in their turn change to bioclastic grainstones since the layer Dj17/13 (Fig. 16.7-16.8); the latter includes brachiopod spines, crinoids and cyanobacterial mats (16.8). It should be noted that, unlike the base, the upper part of this interval is devoid of mudsupported carbonate rocks. Most notably, the layers of Dj17/12 (Fig. 17.1-17.2) and Dj17/11 (Fig. 17.3) are of bioclastic grainstone facies and appear to be storm deposits. Successive layers of stromatoporoids are observed on the ca. 25 cm layer Dj17/3, which unfortunately could not be observed in the sampled rocks and thin section. The skeleton was made of horizontal layers (the laminae) supported by upright rod-like structures (Fig. 13.3). These laminar stromatoporoids grew up to 30 mm in height and 60 mm in width. However, the photomicrograph of thin sections reveals a lot of Umbella (Fig. 17.4). The overlying Dj17.2 layer can be defined as oncolitic grainstone and obviously differs from all layers observed within this interval; thus in addition to Dj17/3, this oncolitic grainstone layer can be used as a marker bed. Dj17/2 is overlapped by peloidal grainstone layers of Dj17/1 and Dj17/orb. Dj17/orb. is very rich in brachiopods and yielded several hundred brachiopod specimens. At the first view, rhynchonellide and spiriferide brachiopods appear to be dominant within this assemblage. Dj17/orb is closing the Interval 4. It is also worth noting that the whole section is uncomformably covered by the Eocene algal limestones. (5-6) Dj17/1, peloidal grainstone. (7-8) Dj17/orb, peloidal grainstone.

The Noravank section

Frasnian-Famennian carbonate and-siliciclastic deposits are perfectly exposed in a narrow gorge made by the Amaghu River, below the Noravank Monastery (Fig. 18.1) and constitute the Noravank section which has long been considered as the stratotype for the eponymous regional stage. Although the Noravank section is one of the most important sections in this area for documenting both the faunal turnover and lithological changes that occurred in the Late Devonian, this section has never been studied in detail and remains poorly known. Previously this section has been investigated by different paleontologists and stratigraphers (e.g., Abrahamyan, 1957;Arakelyan, 1964;[START_REF] Ginter | Chondrichthyan microfossils from the Famennian and Tournaisian of Armenia[END_REF] through almost the same profile; however, the data they provided regarding both the lithology and stratigraphy contradict each other. More particularly many stratigraphic intervals are overextended, overlooked and represented with incorrect stratigraphic positions. This could be explained by the difficult structural context of the section, as it is composed of folded and faulted sequences which are difficult to follow and observe in the field.

The lower part of the section (Interval 1) consists of ca. 12 m-thick limestones (Fig. 18.1-18.4) that are mainly identified here as peloidal bioclastic grainstones and also include some layers ). These tempestites consist of different broken fragments of brachiopods, crionoids, bryozoans, trilobites, cyanobacterial mats, tentaculites and lithoclasts that are reworked after the deposition. The overlying layer Nv19/60 also includes some Umbella (Fig.

22

.6) which are not observed in the grainstones cropping out below that level, whereas the Nv19/74 At the place, where we observed and sampled the Interval 1, the layers that crop out above the layer Nv19/74 and constitute the ensuing interval were folded and not convenient for measurements as well as sampling. Therefore, in order to avoid errors, it was decided to observe the section 20 meters to the east (to the direction of the Noravank monastery, in front of a small bridge) where we described more or less horizontally laying layers. The overlying Interval 2 is ca. 25 m-thick and mainly composed of intercalations of shales, sandstones and a single layer of bryozoan packstone.

The sandstone (quartz-wacke) layers of this interval, such as Nv19/107 (Fig The Interval 4 is topped by peloidal bioclastic grainstone layers. Abundant brachiopods are described from the packstone/grainstone layers outcropping above the oncolitic layer (Nv17.4). The top of the section is covered by massive red limestones of Permian age [START_REF] Ginter | Chondrichthyan microfossils from the Famennian and Tournaisian of Armenia[END_REF], which are unconformably overlying the Upper Devonian (lower Famennian) rocks (Figs. 18.1,19.4,20). (5-6) Nv17/1. bis (Interval 4), packstone with a lot of sand (5), brachiopod spines and bryozoan fragments (6).

Lithostratigraphic correlations

The three studied sections from Central Armenia (Ertych, Djravank and Noravank) show that they are very similar in their lithostratigraphic evolution. We establish above four lithostratigraphic intervals (Fig. 26) that have been correlated throughout these sections. The Interval 1 is mainly composed of ca. 12 m-thick bioclastic and peloidal grainstones and a few layers of tempestite (e.g., ). These grainstones contain peloides, shell fragments of brachiopods, gastropods, ostracods, dasycladacean algae, rare bryozoans and cyanobacteria. The tempestites are more common within the Interval 1 of Djravank and Noravank sections than in the Ertych section.

In addition to peloides and quartz grains, these storm deposits contain abraded fragments of brachiopods, gastropods, ostracods and less commonly tentaculites that were sorted mechanically 16

.5-16.6) cropping out in the lower-middle parts. Its second peculiarity lies in the layer below the oncolitic grainstones (Dj19/2), which includes successive layers of stromatoporoids (Fig. 13.3) that was not observed below the oncolitic layer of the other two sections.

Although these four intervals vary slightly in thickness and lithological composition depending on the section, their general composition is quite similar. Most importantly, these intervals are easy to distinguish in the field and they have a fairly wide geographic distribution (the Ertych and Djravank sections are less than a kilometer apart and both of them are ca. 5 Km away from the Noravank section); thus they are mappable and may be more useful for future geological mapping than the "formations" introduced by Arakelyan (1964), which as discussed by Serobyan et al. (2019a, b) are defined based on their fossil assemblages (mainly brachiopods) and not on their lithology.

Sequence stratigraphy and paleoenvironmental interpretation

The intervals constituting our studied sections have similar lithostratigraphic composition; thus it can be reasonably assumed that these intervals were developed under the same depositional environment (e.g., depth, carbonate production). More particularly, the stratigraphic development of sedimentary rocks of Interval 1 in all three sections clearly displays an aggradational stacking pattern that is interpreted as representing a highstand system tract (HST). The lithological composition and the fossil fauna described in the Interval 1 allow considering that it was accumulated in an internal ramp environment. However, the erosional surface (ES) observed at the top of this interval (e.g., Nv19.74) and the overlying black shales observed in all sections, which can be considered as a maximum flooding surface (MFS), mark a change in depositional trend [START_REF] Catuneanu | sequence stratigraphy of clastic systems: concepts, merits, and pitfalls[END_REF][START_REF] Catuneanu | Sequence stratigraphy: guidelines for a standard methodology[END_REF]. The deposition of Interval 2, apparently records a deepening-upward (transgressive) trend. Hummocky cross-stratification (HCS) is observed within this interval in all three sections, which is an important sedimentary structure mainly found in sandstones formed by the wave action at the shoreface-offshore transition (middle ramp) [START_REF] Woolfe | Devonian depositional environments in the Darwin Mountains: Marine or non-marine?[END_REF]. It is a form of cross-bedding described mainly in sandstones, which usually characterizes a wave dominated facies and formed at a depth of water below fair weather wave base (FWWB) and above storm wave base (SWB). Consequently, the presence of HCS structure suggests that the sedimentary rocks of Interval 2 were deposited on a median ramp environment [START_REF] Dott | Hummocky Stratification: Significance of Its Variable Bedding Sequences[END_REF]. While, the vertical buildup exactly marks the end of a HST and beginning of a TST. The base of Interval 4 in the Noravank section is represented by a distinct layer of crinoidal grainstone (Nv19/218), which clearly points to a change in depositional environment and matches with a HST. The Nv19/218 is covered by black shales (flooding surface?) and bioclastic grainstones. This crinoidal layer is not observed in the Ertych and Djravank sections. This oncolitic grainstone layer that is observed in all sections, in addition to cyanobacterial mats also includes peloides and Umbella typical of fresh water environment, which allows me to assume that it was formed in a shallow inner lagoon type of environment. Evidently, Nv17/4 records a significant drop in sea level. The accumulation of the upper part of Interval 4 in a lagoonal environment is further evidenced by the sparite-filled fenestrae observed within the layer Dj19/4, which also containes plenty of Umbella. However, the overlying tentaculite/bryozoan packstones feature deeper facies, apparantly associated with a transgression that generally results from a rising relative sea level [START_REF] Catuneanu | Principles of Sequence Stratigraphy[END_REF][START_REF] Catuneanu | Sequence stratigraphy: guidelines for a standard methodology[END_REF].

Chapter 4

Systematic paleontology

the Order Rhynchonellida (instead of the one suggested by Sartenaer (2001Sartenaer ( , 2003))), Copper (2002) for the order Atrypida, Alvarez and Rong (2002) for the Order Athyrida and [START_REF] Carter | A revised classification of the spiriferid brachiopods[END_REF]) Johnson (2006) for the Order Spiriferida. The term Athyrida is used here according to the recommendation made by [START_REF] Copper | Early athyride brachiopod evolution through the Ordovician-Silurian mass extinction and recovery, Anticosti Island, eastern Canada[END_REF].

Order Rhynchonellida [START_REF] Kuhn | Lehrbuch der Paläozoologie: Stuttgart[END_REF] Superfamily Rhynchotrematoidea Schuchert, 1913Family Trigonirhynchiidae Schmidt, 1965Subfamily Trigonirhynchiinae Schmidt, 1965 Genus Sartenaerus Özdikmen, 2008

See [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF], p. 530.

Sartenaerus baitalensis (Reed, 1922) See Serobyan et al. (2021), p. 530, Figs. 3-4.

Sartenaerus charakensis (Brice, 1967) See [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF]), p. 533, Figs. 5.1-5.10, 6. Genus Porthmorhynchus Sartenaer, 2001 Porthmorhynchus? sp.

See [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF]), p. 536, Figs. 5.11-5.15, 7. Subfamily Ripidiorhynchinae Savage, 1996 Genus Ripidiorhynchus Sartenaer, 1966a Type species.-Terebratula livonica von Buch, 1834.

Ripidiorhynchus gnishikensis (Abrahamyan, 1959) Plate 1.1-1.5; Figures 28,30; Table 1 1959 Camarotoechia strugi Nal. subsp. gnishikensis n. subsp.; Abrahamyan, p. 6, pl. 2, figs. 5-7. 1964 Camarotoechia strugi Nal, subsp. gnishikensis Abrahamyan, 1959;Arakelyan, p. 63, 67, 70, 74, 77, 92, 93. 1975 Ripidiorhynchus (Camarotoechia) strugi var. gnishikensis (Abr.); Arakelyan et al., p. 22. 2018a Ripidiorhynchus gnishikensis (Abrahamyan, 1959); Pakhnevich in Alekseeva et al.,p. 852,905,pl. 6,pl. 14,figs. 6 and 18;.

2019 Ripidiorhynchus gnishikensis (Abrahamyan, 1959); Serobyan et al.,p. 7.

Neotype.-Although Abrahamyan (1959: pl. 2, figs. 5-7) designated a holotype among the three specimens she illustrated, neither the holotype nor other specimens examined in her publication can be traced within Abrahamyan's collection stored at the IGSNASRAGM and are considered as lost.

Therefore, the single specimen (IGSNASRAGM 3927/PS 3033) figured in Plate 1.1-1.5 is hereby designated as the neotype.

Occurrence.-Ripidiorhynchus gnishikensis was first described in Armenia by Abrahamyan (1959), in the Frasnian sequences of the Gnishik section (Fig. 1). Later it was reported by Arakelyan (1964) in the Frasnian Baghrsagh Regional Stage of the Baghrsagh and Danzik sections as well as in the lowest Famennian Noravank Regional Stage of the Noravank, Ertych and Gyumushlug sections (Fig. 1) within a brachiopod assemblage composed of Frasnian spiriferide brachiopods. Presumably Arakelyan (1964) confused R. gnishikensis with a lower Famennian representative of that genus, most likely with R. djravankensis n. sp. as Abrahamyan's species occurred only in the Frasnian.

Unfortunately, the specimens identified as R. gnishikensis by Arakelyan cannot be traced within his collection and are considered as lost, which precludes the opportunity of re-examination and revealing this taxonomic confusion. However Arakelyan et al. (1975) mentioned R. gnishikensis amongst the biostratigraphically significant species characterizing the Frasnian in Armenia.

Afterwards, Pakhnevich in Alekseeva et al. (2018a) examined a huge material from several localities in Nakhichevan and specified that it actually occurs in the Baghrsagh Regional Stage, correlated with the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis brachiopod Zone of Rzhonsnitskaya and Mamedov (2000), confirming the viewpoint of Arakelyan et al. (1975).

Additionally, it is judicious to remind here that recent sampling also revealed the presence of this species only in the Frasnian sequences.

Description.-Shell small-sized (up to 17.9 mm in width, 16.2 mm in length, 13.7 mm in thickness) Ornamentation of low, angular ribs, originating at beaks and thickened anteriorly; ribs in sulcus and on fold larger than those present on flanks; 10-13 ribs on flanks, 4-5 ribs in sulcus, 5-6 ribs on fold, one pair of faint ribs developed on the flanks of the fold and on the margins of the sulcus; ribs wider than interspaces.

(
Ventral valve interior (Fig. 28 (Abrahamyan, 1959). Abbreviations: Wwidth of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

Remarks.-Ripidiorhynchus gnishikensis was described initially by Abrahamyan (1959) as a subspecies of Camarotoechia strugi Nalivkin, 1941 based on some external differences observed within the Armenian material such as the finer ribs and a lower trapezoidal tongue. Note that [START_REF] Nalivkin | Brakhiopody glavnogo devonskogo polya[END_REF] species was considered by [START_REF] Sokiran | Frasnian-Famennian extinction and recovery of rhynchonellid brachiopods from the East European Platform[END_REF] as a synonym of R. livonicus (von Buch, 1834). Based on the detailed study of material from Nakhichevan, Pakhnevich (in Alekseeva et al., 2018a) raised the subspecies gnishikensis to the species level assigning it at the same time to the genus Ripidiorhynchus, based on the general shape and outline, the well-developed sulcus and fold beginning at some distance from the beaks, the ventrally convergent dental plates as well as the presence of a low septum and a covered septalium. Occurrence. -Sartenaer (2001) discussed and discarded several reports pointing out the presence of Ripidiorhynchus representatives in the lower Famennian of Afghanistan (Brice and Lang, 1968;Brice, 1971;[START_REF] Farsan | Frasnian mass extinction -A single catastrophic event or cumulative? Faunistic investigations at the Frasnian-Famennian boundary in South-central Asia[END_REF] and New Mexico (Cooper and Dutro, 1982;[START_REF] Dutro | The Late Devonian extinction event as recorded by articulate brachiopod ranges in the United States of America: Biostratigraphie du Paléozoique[END_REF]. He explained that previous authors mistakenly attributed some species to this genus coming from sections where the Frasnian-Famennian boundary is poorly constrained and concluded that no evidence points the presence of Ripidiorhynchus in the Famennian. Moreover, Sartenaer (2001) rejected its presence in Iran [START_REF] Gaetani | Brachiopods and mollusks from Geirud Formation, Member A (Upper Devonian and Tournaisian): The geology of the Upper Djadjerud and Lar Valleys (North Iran): 2[END_REF] and Afghanistan [START_REF] Farsan | Frasnian mass extinction -A single catastrophic event or cumulative? Faunistic investigations at the Frasnian-Famennian boundary in South-central Asia[END_REF]. Nevertheless, Sokiran (2006) Ventral valve interior (Fig. 29) with stout, short intrasinal dental plates, slightly converging ventrally; teeth massive, subrectangular in outline; central apical cavity wide; lateral apical cavities moderately filled in by callus.

Dorsal valve interior (Fig. 29) with low, stout septum supporting a deep, Y-shaped, and anteriorly covered septalium; hinge plates united.

Etymology.-In reference to the type locality of the species (Djravank section) (Fig. 1). width/width of sulcus (3) of Ripidiorhynchus djravankensis n. sp. and R. gnishikensis (Abrahamyan, 1959).

Abbreviations: n, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation.

Shell ontogeny.-The size distribution of R. djravankensis n. sp. during the growth, as represented by the scatter plots of the width/length, the width/thickness and the width/width of sulcus, shows a continuous and progressive growth with no distinct stages (Fig. 30). The relative proportions represented by sufficient material remain constant (linear regression: y = ax+b; significant probability value: p < 0.01***) whatever the degree of development of individuals (Fig. 30). With an exception of the thickness, the correlation is positive with width varying proportionally with length and width of sulcus. The shell outline highly varies in its thickness, more often having a shell with thickness exceeding length; the fold height is also impermanent, shifting from high to very high and thus changing also the tongue height. To complete the scatter plots, the measurements (in Remarks.-The external and internal features of the newly defined species match well with the diagnosis of Ripidiorhynchus Sartenaer, 1966a.

R. djravankensis n. sp. differs from R. livonicus [START_REF] Buch | Über Terebrateln, mit einem Versuch, sie, zu classificiren und zu beschreiben[END_REF], which was revised by Sokiran (2006), from lower Frasnian Sargaevo Horizon of northwestern Russia (Sartenaer, 1966a), Latvia, and Lithuania, by its wider and deeper sulcus, its wider fold that is flat-to slightly round-topped at front, and fewer and coarser ribs. Internally, the new species differs by the development of relatively stout callosities in lateral apical cavities and by narrow septalium.

R. djravankensis n. sp. looks like the lower-middle Frasnian species R. aldogus [START_REF] Nalivkin | Brakhiopody glavnogo devonskogo polya[END_REF] as revised by Sokiran (2006), occurring within the Snetogorsk and Pskov beds of northwestern Russia, but the new species differs by having more developed sulcus and fold, a suberect to erect beak as well as a high tongue.

R. djravankensis n. sp. is close to two species recognized within the Zadonsk Horizon of central Russia, namely R. cernosemicus [START_REF] Nalivkin | Opisaniye fauny[END_REF] and R. huotinus (de Verneuil, 1845), but it differs from the former by its more globular shell outline, more convex lateral profile and having fewer ribs. R. djravankensis n. sp. is distinguished from the latter by its wider fold and sulcus, suberect to erect beak and having fewer ribs.

R. djravankensis n. sp. is easily distinguished from R. griasicus [START_REF] Nalivkin | Opisaniye fauny[END_REF] sensu Sokiran (2006) (Reed, 1922). 1, Relation between shell width and length. (Reed, 1922). Abbreviations:

W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

Remarks.-Both external and internal features of the Armenian material fit well with Reed (1922)'s description of Cyphoterorhynchus koraghensis, which is known from the middle-upper Frasnian strata of different parts of the Gondwanan terranes. More precisely, it was described in Chitral (northwestern Pakistan; Reed, 1922), Afghanistan (Brice, 1971), Iran (Sartenaer, 1966b) and probably Turkey [START_REF] Gourvennec | Upper Devonian Brachiopods from Eastern Taurus (Turkey)[END_REF]. However, it should be stressed that the teeth and dental sockets of Armenian material lack crenulation, contrary to what it is observed in specimens from Chitral. [START_REF] Gourvennec | Upper Devonian Brachiopods from Eastern Taurus (Turkey)[END_REF] illustrated a single specimen from the Upper Devonian (probably from the lower Frasnian) of Eastern Taurus (Turkey) and identified it as C. koraghensis. Although he did not examine its internal structure, this assignment seems to be the most satisfactory as it does not differ superficially from Reed's material. Moreover, his assignment can be further supported by the resemblance of Devonian brachiopods of Turkey with those described in Afghanistan, Iran, Pakistan and the Lesser Caucasus.

According to Sartenaer (1966b), C. k. koraghensis differs from C. k. interpositus Sartenaer, 1966b, which is a transitional form between the nominal species and C. arpaensis (Abrahamyan, 1957), by its transversely ovate shell outline, coarser and fewer ribs. It is also worth emphasizing that Pakhnevich in Alekseeva et al. (2018a) considered the latter subspecies to be synonym of C. arpaensis, since he observed in Abrahamyan's species the main characteristics (e.g. number of costae, shell width), which were supposed to distinguish the subspecies.

C. k. koraghensis is distinguished externally from C. arpaensis (Abrahamyan, 1957) by its suptrapezoidal tongue, serrate anterior and lateral commissures as well as coarser and fewer ribs.

The latter is one of the most biostratigraphically valuable species in the Lesser Caucasus and used for the definition of a Frasnian brachiopod zone, namely the Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000). However, our recent sampling did not reveal the presence of this species in the Frasnian of our studied sections, which possibly means that in Armenia it occurs in older strata. Although Abrahamyan (1957) did not designate a type specimen among the two she illustrated, Pakhnevich in Alekseeva et al. (2018a) considered the only photographed specimen (Abrahamyan, 1957: pl. 5, fig. 6) as the holotype.

According to the Article 73 of the International Commission on Zoological Nomenclature (1999), the holotype of a new species can only be fixed in the original publication and by the original author, and thus Abrahamyan's specimen selected by Pakhnevich cannot be considered as the valid holotype. Moreover, the specimen chosen by Pakhnevich from Abrahamyan (1957)'s publication is lost. Therefore, a lectotype must be designated among the specimens of Abrahamyan (1957)'s collection, which is currently stored at the IGSNASRAGM.

Contrary to Pakhnevich (in Alekseeva et al., 2018: p. 910)'s statement, Cyphoterorhynchus arpaensis does not occur in the Frasnian of Belgium, where the genus has never been recovered. In addition, it is worth stressing that the genus is also known from Libya [START_REF] Mergl | A palaeontological review of the Devonian and Carboniferous succession of the Murzuq Basin and the Djado Sub-Basin[END_REF] and Spain [START_REF] Pardo | Bioestratigrafía del Devónico de la Región de Almadén[END_REF], thus only in Gondwanan terranes.

Genus Gesoriacorostrum Sartenaer, 2003 Gesoriacorostrum? sp.

See [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF] 1997 Atrypa (Planatrypa) ertichensis; Komarov,p. 87,pl. 1,fig. 5. 2018a Atrypa (Planatrypa) ertichensis; Grechishnikova in Alekseeva et al.,p. 24,26.

Holotype.-An articulated specimen (270/3-54; the holotype is the 270th collected specimen by [START_REF] Abrahamyan | Novyye vidy brakhiopod iz famenskikh otlozheniy Armyanskoy SSR[END_REF], from the 3th layer of Ertych section) from the Frasnian of Ertych section, Armenia (Abrahamyan, 1959;pl. 1, fig. 1a-d). It is currently housed at IGSNASRAGM and is catalogued under collection no. 3/1. In fact, in addition to the holotype, there is another specimen of the type of material that was marked with the same number as the holotype, but was not illustrated by Abrahamyan (1959). Therefore, it was decided to illustrate the second specimen to demonstrate its original mark and the difference between it and the real holotype.

Occurrence.-Although Abrahamyan (1959) initially described this species from the Frasnian strata of Armenian sections, [START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF] specified that it mainly occurs in the upper Givetian Adolfia zickzack Zone of Rzhonsnitskaya and Mamedov (2000) and occasionally in the lower part of the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone. However, as it was turned out later Adolfia zickzack Zone of Rzhonsnitskaya and Mamedov (2000) is early Frasnian in age based on conodonts and rugoe corals (see Grechishnikova in Alekseeva et al. (2018a); p. 24-25).

Thus, it appears that Atryparia (Costatrypa) ertichensis (Abrahamyan, 1959)

occurs in the lower

Frasnian of the Lesser Caucasus.

Description.-Shell medium-sized (up to 30.1 mm in width, 29.7 mm in length and 16.9 mm in thickness), strongly dorsibiconex, shield-shaped to semi-elliptic in outline; hinge line shorter than the maximum width; the maximum height and width of the shell in the posterior third of the shell;

anterior margin rounded to straight; anterior commissure undulose to slightly uniplicate.

Ventral valve slightly convex in posterior view, with anterolateral parts inclined to become flat; shoulder lines indented by umbo; beak small, suberect; foramen small, apical; sulcus wide, poorly-defined, very shallow, perceptible only at front, flat-bottomed at front; tongue low, wide, semi-rounded to semi-elliptic in outline, not perpendicular to commissural plane.

Dorsal valve sharply inflated with convex flanks sloping steeply towards the lateral commissures; highest at about midlength or more posteriorly to it, then decreasing progressively towards the anterior margin; fold absent.

Ornamentation of tubular-imbricate, coarse ribs originating at beaks and becoming fainter towards lateral cardinal extremities; ribs increasing principally by bifurcation on the ventral valve and by intercalation on the dorsal valve; 65-72 ribs on the entire shell; generally 5-6 ribs per 5 mm at anterior margin; growth lamellae more crowded near the anterior and lateral margins, extending into frills (Pl. 3.1).

Internal morphology not observed.

Material.-Three articulated specimens of Abrahamyan's collection and two newly recovered specimens from the Frasnian of Ertych section.

Remarks.-Initially described by Abrahamyan (1959), this species was mistakenly considered as a variety of Atrypa tubaecostata Paeckelmann, 1931, based on some external differences observed in the Armenian material such as larger size, inflated dorsal valve and the presence of sulcus.

However, in 1974, Abrahamyan raised it at the species level, but its affinities at the genus level still remain unclear. Mamedov and Rzhonsnitskaya (1985) attributed the latter to the genus

Spinatrypina, but again without study of its main fundamental features such as the ornament and internal morphology. Afterwards, [START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF] re-assigned it to Atrypa (Planatrypa) owing to the general shell shape, external ornamentation and absence of dental plates from the ventral interior. However, the frilly ornamentation described on Abrahamyan's species (see Pl. Devonian Atrypa (Planatrypa) [START_REF] Struve | Beiträge zur Kenntnis devonischer Brachiopoden[END_REF]. Additionally, it is worth noting that the examination of some of the type specimens of Abrahamyan's species established that the specimens described in Nakhichevan by [START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF] are conspecific with the ones of Armenian sections.

Subfamily Spinatrypinae [START_REF] Copper | Devonian Atrypoids from western and northern Canada[END_REF] Genus Spinatrypa [START_REF] Stainbrook | Substitution for the preoccupied name Hystricina[END_REF] Subgenus Spinatrypa (Spinatrypa) [START_REF] Stainbrook | Substitution for the preoccupied name Hystricina[END_REF] Type species.-Atrypa hystrix var. occidentalis Hall, 1858.

Spinatrypa (Spinatrypa) sp.

Plate 3.8-3.13

Occurrence.-The specimens were collected from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) of Ertych section (Fig. 1).

Description.-Shell medium-sized (ca. 37.1 mm in width, 32 mm in length and 19 mm in thickness), sharply dorsibiconvex, wider than long, semi-elliptic in outline; cardinal extremities appear to be rounded (although in most of the specimens, they are incomplete); anterior margin flat;

anterior commissure uniplicate.

Ventral valve slightly convex in posterior and lateral profile views with maximum convexity in the umbonal area; anterolateral parts inclined to become flat; umbo inflated, prominent; beak suberect; foramen unobserved due to deficient preservation; sulcus wide but extremely shallow; tongue low, wide, largely rounded in outline, not perpendicular to commissural plane.

Dorsal valve inflated, regularly curved in posterior and lateral profile views, with convex flanks sloping steeply towards the lateral commissures; posterolateral areas inclined; highest at about midlength or slightly anteriorly to it, then progressively decreasing towards the anterior margin; fold absent.

Ornamentation of up to 30 undulose, coarse ribs increasing generally by bifurcations on both valves; generally 3-4 ribs per 5 mm at anterior margin; growth lamellae covered by concentric microlines (6-8 per mm) and more closely spaced near the commissure, sometimes thickened as growth varices.

Internal morphology unknown.

Material.-Two partly exfoliated articulated specimens.

Remarks.-Spinatrypa (Spinatrypa) [START_REF] Stainbrook | Substitution for the preoccupied name Hystricina[END_REF] is mainly known from the upper Givetianupper Frasnian shallow water carbonate/siliciclastic deposits of Northern America and Weastern Europe. Our material is closely related to the subgenus Spinatrypa (Spinatrypa) based on its size, semi-elliptic outline, strongly dorsibiconvex profile, slightly uniplicate anterior commissure, subtrapezoidal tongue, coarse and undulose ornamentation. However, it is doubtfully assigned to this subgenus as the insufficiency of our material precludes the possibility to examine its internal morphology. Complementary material is needed to reach a more confident identification.

Additionally, it is also pertinent to stress that this is the first documentation of this subgenus in the Frasnian of the Lesser Caucasus.

Subfamily Variatrypinae Copper, 1978 Genus Desquamatia Alekseeva, 1960 Subgenus Desquamatia (Seratrypa) [START_REF] Copper | Frasnian Atrypidae[END_REF] Type species.-Dequamatia (Seratrypa) pectinata [START_REF] Copper | Frasnian Atrypidae[END_REF].

Desquamatia (Seratrypa) abramianae [START_REF] Komarov | Novye Desquamatia (Brachiopod) vidy iz devonskikh otlozheniy Zakavkaz[END_REF] Plate 4; Figure 33-34; Table 4 1992 Desquamatia (Seratrypa) abramianae Komarov,p. 99,pl. 1, 1997 Desquamatia (Seratrypa) abramianae Alekseeva and Komarov,p. 151,pl. 4,pl. 5,.

Holotype.-The holotype (VI-223/3a; Komarov, 1992: pl. 1, fig. 3) is from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) of the Danzik section, left bank of the Arpa River, Nakhichevan. It is currently housed at the VSGM.

Occurrence.-This species is only found in the SAB. More particularly, according to [START_REF] Komarov | Novye Desquamatia (Brachiopod) vidy iz devonskikh otlozheniy Zakavkaz[END_REF][START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF], it is restricted to the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Nakhichevan. Our examined material comes from the same Frasnian strata of the Ertych, Djravank and Noravank sections (Fig. 1).

Description.-Shell medium-sized (up to 39.6 mm in width, 37.7 mm in length and 27.9 mm in thickness) (Table 4), wider than long to longer than wide, sharply dorsibiconvex, relatively equidimensional, highest and widest at about mid-length or more posteriorly to it, semi-elliptic to semi-rounded outline; hinge line shorter than widest; anterior margin slightly rounded to straigth;

anterior commissure undulose to slightly uniplicate.

Ventral valve inflated posteriorly with flanks sloping moderately towards the lateral commissures; highest in the posterior third of the valve, then decreasing progressively towards the anterior margin; umbo inflated, prominent; beak acute, erect; interarea very small, concave, anacline to hypercline; foramen and deltidial plates unobserved due to deficient preservation; sulcus very shallow and perceptible only at front, flat-to slightly round-bottomed at front; tongue low, wider than high, semi-rounded to semi-elliptic, not perpendicular to commissural plane.

Dorsal valve sharply inflated with convex flanks sloping steeply towards the lateral commissures; highest at about midlength or more posteriorly to it, then decreasing progressively towards the posterior margin; umbo inflated; fold not developed. Ornamentation of fine, tubular ribs increasing by bifurcation and intercalation on both valves; generally 125-140 ribs on the entire shell, 5-6 ribs per 5 mm at anterior margin; growth lamellae more crowded near the lateral and anterior margins.

Ventral valve interior (Fig. 33) with stout but short dental plates; dental nuclei relatively large, well-marked; teeth massive, simple; central apical cavity not filled in by callosities.

Dorsal valve interior (Fig. 33) with a weak cardinal process in form of a pad, enclosed within the cardinal pit; dental sockets not deep, divided by a median crest; crural bases stout; crura ventrally directed; jugal processes and spiral cones not observed. significant probability value: p < 0.001*** whatever the degree of development of individuals (Fig. 34). Moreover, the correlation is positive with width varying proportionally with length, thickness and width of sulcus. To complete the scatter plots, the measurements (in mm) of numerous individuals of D. (S.) abramianae are also presented in Table 4. Remarks.-Although [START_REF] Komarov | Novye Desquamatia (Brachiopod) vidy iz devonskikh otlozheniy Zakavkaz[END_REF][START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF]) examined a huge collection of specimens identified as Desquamatia (Seratrypa) abramianae, he illustrated only a few partly exfoliated specimens, which were primarily devoid of most fundamental features such as ornamentation. Moreover, it is pertinent to highlight here that Komarov represented only a few serial sections displaying the ventral interior, whereas the dorsal one remains unknown. Therefore, we herein represent the close-up of its ornamentation, the internal morphology of both valves in details and different measurements as well as ratios in order to permit to perform statistics to document the intraspecific variation of this species. Additionally, it is worth noting that our material appears to be conspecific with the specimens illustrated by [START_REF] Komarov | Novye Desquamatia (Brachiopod) vidy iz devonskikh otlozheniy Zakavkaz[END_REF][START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF] from the Frasnian strata of Nakhichevan.

Order Athyrida Boucot, Johnson, andStaton, 1964 Suborder Athyridina Boucot, Johnson, andStaton, 1964 Superfamily Athyroidea Davidson, 1881 Family Athyridae Davidson, 1881 Subfamily Cleiothyridininae Alvarez, Rong, and Boucot, 1998 Genus Crinisarina Cooper and Dutro, 1982 Crinisarina pseudoglobularis [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF] See [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF]), p. 543, Figs. 14-15. Order Spiriferida Waagen, 1883Suborder Spiriferidina Waagen, 1883 Superfamily Cyrtospiriferoidea Termier and Termier, 1949 Family Cyrtospiriferidae Termier and Termier, 1949 Subfamily Cyrtospiriferinae Termier and Termier, 1949 Cyrtospiriferinae gen. et sp. 1

Plate 5.1-5.6

Occurrence-The single specimen examined here is recovered from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in the Ertych section.

Description.-Shell medium-sized (up to 26.9 mm in width, 21.7 mm in length and 16.9 mm in thickness), wider than long, ventribiconvex, rounded transverse in outline; hinge line narrower than widest; highest in the posterior third of the valve; cardinal extremities obtuse or slightly mucronate;

anterior margin nearly straight; anterior commissure slightly uniplicate.

Ventral valve strongly inflated, with convex flanks sloping steeply towards lateral commissures; umbo inflated, prominent; beak erect, acute; interarea apsacline, triangular, low to moderately high, well-defined, delthyrium unobserved; sulcus very narrow, shallow, originating from beak, poorly delimited, flat-to slightly round-bottomed at front; tongue very low, semi-elliptic in outline.

Dorsal valve inflated, semi-circular to semi-elliptic in outline, with flanks sloping gently to moderately towards lateral commissure; highest in the posterior third of the valve, then decreasing gradually towards anterior margin; umbo prominent, protruding beyond the posterior margin with an acute beak, interarea linear, orthocline; fold unobserved due to poorly preservation state.

Ornament of low, flattened ribs that are poorly preserved.

Internal morphology unknown.

Material examined.-One single exfoliated articulated specimen.

Remarks.-This very restricted material is attributed to the Family Cyrtospiriferidae as defined by Johnson (2006) because of its inflated shell and the development of ribs in the sulcus and on fold. It is further assigned to the Subfamily Cyrtospiriferinae based on its wide hinge line and rounded transverse outline. However, the lack of knowledge about the internal features and the microornament of this specimen precludes a generic assignment. Cyrtospiriferinae gen. et sp. 1 differs from Cyrtospiriferinae gen. et sp. 2 (Pl. 5.7-5.9) by its more rounded shell, inflated ventral valve, nearly straight anterior margin as well as narrow and shallow sulcus.

Cyrtospiriferinae gen. et sp. 2

Plate 5.7-5.9

Occurrence.-The specimens were collected from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) of the Ertych section (Fig. 1).

Material.-Two partly exfoliated ventral valves.

Remarks.-These poorly preserved ventral valves (up to 32 mm in width) are inflated and characterized by a transversely oval outline, with a deep sulcus originating from the beak. The ornamentation consists of simple, low ribs which are slightly wider than those present on flanks (Pl.

11.9). Additional material is required to reach a better identification.

Genus Cyrtospirifer Nalivkin in Fredericks, 1924 Type species.-Spirifer verneuili Murchison, 1840.

Remarks.-Abrahamyan (1957: pl. 9, figs. 2-3) illustrated some specimens identified as

Cyrtospirifer verneuili [START_REF] Murchison | Description de quelques-unes des coquilles fossiles les plus abondantes dans les couches de´voniennes du Bas-Boulonnais[END_REF] from the lower Famennian Cyrtospirifer orbelianus Zone of Central Armenia and indicated that in this country, this species occurs in the Frasnian-uppermost Famennian interval. Although Abrahamyan (1957) didn't illustrate the internal morphology and type of micro-ornament of her material, this assigment seems to be the most satisfactory as the specimens she illustrated are closely related to the type material described from Ferques (France).

Later, Abrahamyan (1974) illustrated a single specimen from the upper Famennian of Armenia and assigned it to C. verneuili. However, it is evident that this specimen does not share affinities with Murchison's species as it displays more rounded outline as well as small and mucronate cardinal extremities, which is not the case of C. verneuili. It is judicious to remind here that the type material of Murchison's species is described from the Frasnian strata of Ferques. Therefore, the occurrence of C. verneuili in the upper Famennian of Armenia must be excluded and Abrahamyan (1974)'s specimen should be re-investigated. It is also noteworthy that recent sampling did not reveal the presence of this species in the three sections studied.

Cyrtospirifer? sp. 1

Plate 5.10-5.11

Occurrence.-The specimens were collected from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) of the Ertych section (Fig. 1).

Material.-Two partly exfoliated articulated specimens.

Remarks.-This very restricted material is attributed to the Family Cyrtospiriferidae as defined by Johnson (2006) because of its inflated shell and the development of ribs in the sulcus and on fold. It is further assigned to the Subfamily Cyrtospiriferinae based on its wide hinge line and rounded transverse outline. However, the lack of knowledge about the internal features and the microornament of this specimen precludes a generic assignment.

Cyrtospirifer? sp. 2

Plate 5.12-5.16; Figure 35 Occurrence-The specimens are recovered from the lower Famennian Cyrtospirifer orbelianus brachiopod Zone of Abrahamyan (1957), which corresponds to the Cyrtiopsis orbelianus-Cyrtiopsis armenicus brachiopod Zone of Rzhonsnitskaya and Mamedov (2000).

Description.-Shell medium-sized (attaining 34 mm in width, 17.9 mm in length and 20.1 mm in thickness), wider than long, markedly ventribiconvex, rounded subtrapezoidal in outline; widest at hinge line; highest close the hinge line; cardinal extremities probably acute (broken); anterior margin nealy straigth; anterior commissure uniplicate.

Ventral valve highly inflated, with convex flanks sloping steeply towards lateral commissures; highest near the hinge line, then decreasing gradually towards anterior margin; umbo inflated, prominent; beak small, acute, erect; interarea very high, well-defined, catacline, triangular, generally slightly concave; delthyrium wide, almost completely covered by a pseudodeltidium that is poorly preserved; sulcus wide, relatively deep, originating from beak, round-bottomed at front; tongue not high, relatively wide, not perpendicular to commissural plane, subcircular to subogival in outline.

Dorsal valve moderately inflated with flanks sloping gently towards lateral commissures; highest in the posterior third of the valve, then progressively declining towards the anterior margin;

interarea nearly flat, linear, orthocline; fold wide, well-delimited, moderately high, starting from beak and widening anteriorly, round-topped at front.

Up to 22 simple, low ribs on flanks with top rounded; in sulcus and on fold, at least 10 ribs (poorly preserved) increasing by bifurcations and narrower than those on flanks; interspaces narrower than ribs; micro-ornament is not preserved.

Ventral interior (Fig. 35) with relatively stout dental plates, intrasinal or subsinal posteriorly but extrasinal more anteriorly; delthyrial plate well-developed, situated close to the delthyrial thickening formed by accretion of strong apical callosities; lateral apical cavities moderately infilled.

Dorsal valve interior (Fig. 35) with unsupported ctenophoridium consisting of relatively short lamellae; hinge plates divided; crural bases dorsally convergent; spiralia unknown. Material.-Two articulated specimens from the Djravank section.

Remarks.-Our material is closely related to the genus Cyrtospirifer based on its rounded subtrapezoidal outline, widest at hinge line, ventribiconvex profile, well-developed fold and sulcus, the type of ornamentation (low, simple ribs on flanks and fainter as well as bifurcating ribs in sulcus and on fold) and the presence of a well-developed delthyrium. However, it is doubtfully assigned to this genus as the orientation of its dental plates (converging ventrally), the development of delthyrium near the umbonal region and the presence of an apical callosity in the ventral interior are in contradiction with the diagnosis of the genus. Although its external morphology resembles Cyrtospirifer? sp. 1 in terms of general shape and outline, this very restricted material is separated as the internal structure of Cyrtospirifer? sp. 1 is unknown and it comes from the Frasnian strata.

Additionally, it is worth mentioning that Cyrtospirifer? sp. 2 is much smaller than Cyrtospirifer? sp.

1 and has fewer ribs. Additional material is needed to reach a more confident identification.

Cyrtospirifer sp. 1

Plate 5.17-5.21; Figure 36 Occurrence.-The specimens were collected from the lower Famennian orbelianus Zone of Abrahamyan (1957) of the Djravank section (Fig. 1).

Description.-Shell medium-sized (up to 27 mm in width, 20.6 mm in length and 17.6 mm in thickness), wider than long, ventribiconvex, subtrapezoidal in outline, highest at about midlength;

anterior margin straight; anterior commissure uniplicate.

Ventral valve strongly inflated, with convex flanks sloping steeply to moderately towards lateral commissures; highest at about midlength or slightly posteriorly, then decreasing progressively towards anterior margin; umbo inflated, prominent; beak erect; interarea apsacline, strongly concave, low; delthyrium unobserved (concealed by sediment); sulcus narrow, shallow to relatively deep, originating from beak, flat-bottomed at front, well-defined by bounding ribs; tongue low, subtrapezoidal in outline, perpendicular to commissural plane or slightly bent dorsally. Dorsal valve interior (Fig. 36) with supported ctenophoridium that is composed of up to 19 well-developed, relatively long lamellae; hinge plate divided; crural bases stout; spiralia oriented posterolaterally with at least 15 whorls per spiral cone.

Material.-Two partly exfoliated articulated specimens.

Remarks.-The external and internal features observed (e.g., ventribiconvex profile, subtrapezoidal outline, concave and apsacline ventral interarea, well-developed fold and sulcus, long and extrasinal dental plates, the presence of delthyrial plate, supported ctenophoridium) in the two studied specimens indicate affinities to the genus Cyrtospirifer Nalivkin in Fredericks, 1924. However, further specimens are needed to reach a more confident identification at the species level.

Cyrtospirifer pseudoasiaticus n. sp.

Plate 6; Figures 3738; Table 5 Holotype.-An almost complete articulated specimen (IGSNASRAGM 3952/PS 3058;) from the lower Famennian orbelianus Zone of Abrahamyan (1957), which is correlated with the Ertych Regional Stage (Fig. 3); Ertych section (6 km southeast from Areni, Vayots Dzor Province, Central Armenia) (Fig. 1).

Diagnosis.-Shell medium-sized (up to 30 mm in width, 21.5 mm in length and 21.2 mm in thickness) ( Occurrence.-This species is found only in Armenia. More precisely it is described from the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957), which is correlated with the Ertych Regional Stage of Arakelyan (1964) (Fig. 2).

Description.-Shell medium-sized, wider than long, ventribiconvex (rarely equibiconvex), rounded transverse in outline with obtuse cardinal extremities; hinge line narrower than widest; highest in the posterior third of shell; anterior margin emarginate; anterior commissure uniplicate.

Ventral valve strongly inflated with convex flanks sloping steeply towards lateral commissures; highest in the posterior third of the valve, then decreasing progressively towards anterior margin; umbo strongly inflated, prominent; beak straight; interarea well-defined, apsacline, triangular, high, generally slightly concave; delthyrium wide, covered by a pseudodeltidium for most of its height, the latter is formed by several distinct plates; foramen minute, ovate, near the apex; sulcus relatively wide, moderately deep, originating from beak, round-bottomed at front; tongue high, subogival to subcircular in outline, generally not perpendicular to commissural plane.

Dorsal valve subtrapezoidal to rounded subrectangular in outline, inflated, with convex flanks sloping gently to moderately towards lateral commissures; highest at about midlength or slightly posteriorly to it, then decreasing gradually towards anterior margin (but that is not displayed in the specimen of IGNASRAGM 3951/PS 3057 as it is broken); umbo inflated, projecting slightly beyond the posterior margin; interarea linear, orthocline; fold wide, well-delimited, high, originating from beak, round-topped at front.

On flanks, up to 25 (5 ribs per 5-6 mm at anterior margin near sulcus and fold) usually simple, rounded ribs becoming fainter towards lateral cardinal extremities; in sulcus and on fold, up to 20 (usually 16-18) ribs increasing by bifurcations (Pl. 6.16), much narrower than those present on flanks; interspaces narrower than ribs; micro-ornament (Pl. 6.17) of closely spaced growth lines (irregularly thickened as growth varices), capillae occurring both on ribs and in interspaces, and numerous pustules developed on capillae. Ventral valve interior (Fig. 37) with relatively thin, long, divergent dental plates extrasinal posteriorly then becoming subsinal anteriorly; delthyrial plate well-developed; central and lateral apical cavities poorly infilled by callosities; teeth stout. Dorsal valve (Fig. 37) with unsupported ctenophoridium composed of numerous vertical lamellae (ca. 28-30); hinge plates divided; dental sockets shallow; crural bases mediodorsally oriented; spiralia oriented posterolaterally with at least 20 whorls per spiral cone.

Etymology.-In reference to the confusion made with the spiriferide species Cyrtospirifer asiaticus Brice, 1971.

Material.-Twenty-eight articulated specimens and six dissociated valves from the Ertych Regional Stage of the Ertych (twelve articulated specimens and two ventral valves) and Djravank (sixteen articulated specimens and four ventral valves) sections.

Shell ontogeny.-Although our material does not include juveniles, the examination of relatively small specimens (youth stages of growth) show that the latter display all external morphological characters that are typical for this species. The size distributions during the growth, as represented by the width/length, the width/thickness, the width/width of sulcus and the width/ length of dorsal valve plots, show a continuous and progressive growth with no distinct grouping (Fig. 38). The relative proportions of Cyrtospirifer pseudoasiaticus n. sp. represented by sufficient material remain constant (linear regression: y = ax+b; significant probability value: p < 0.001*** whatever the degree of development of individuals). Moreover, the correlation is positive with width varying proportionally with length, thickness, width of sulcus and the length of dorsal valve. To complete the scatter plots, the measurements (in mm) of numerous individuals of Cyrtospirifer pseudoasiaticus n. sp. are also presented in Table 5.

Remarks.-Our material is assigned to Cyrtospirifer Nalivkin in Fredericks, 1924 Cyrtospirifer, which after revision may be proven to belong to different genera [START_REF] Ma | Revision of North American and selected Eurasian Late Devonian (Frasnian) species of Cyrtospirifer and Regelia (Brachiopoda)[END_REF].

C. pseudoasiaticus n. sp. differs externally from C. verneuili [START_REF] Murchison | Description de quelques-unes des coquilles fossiles les plus abondantes dans les couches de´voniennes du Bas-Boulonnais[END_REF] as revised by [START_REF] Ma | Revision of North American and selected Eurasian Late Devonian (Frasnian) species of Cyrtospirifer and Regelia (Brachiopoda)[END_REF], from the uppermost Givetian-upper Frasnian of Western Europe, by its relatively short hinge line, obtuse cardinal extremities, pseudodeltidium formed by several distinct plates and the type of micro-ornament (consisting of capillae and pustules on ribs and in interspaces). Internally, the new species is distinguished by its unsupported ctenophoridium.

The new species displays strong similarities to C. whitneyi [START_REF] Hall | Report on the geological survey of the state of Iowa; embracing the results of investigations made during portions of the years 1855-1857[END_REF] from the middleupper Frasnian of USA and Canada, most notably to those specimens illustrated by Ma and Day (2003: pl. 9, figs. 12-18); however, the former differs externally by its more inflated shell, type of pseudodeltidium (formed by several distinct plates) and having relatively less densely crowded pustules on capillae and in interspaces.

C. pseudoasiaticus n. sp. seems to be similar to C. asiaticus Brice, 1971, a relatively poorly known species, originally described from the lower Famennian of Afghanistan; however C. pseudoasiaticus n. sp. is separable by its comparably less globular shell, short hinge line, obtuse cardinal extremities and foramen near the apex. Internally, the new species differs by its unsupported ctenophoridium. It is also pertinent to remind here that according to Ma and Day (2007) Brice's species might be belonging to Sinospirifer [START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF] this assumption was based on its central hypothyrid foramen and type of its micro-ornament (consisting of numerous small pustules originating from capillae present both on ribs and in interspaces).

The new species differs superficially from C. placitus [START_REF] Stainbrook | Brachiopoda of the Independence Shale of Iowa[END_REF] 39; Table 6 Occurrence.-The specimens were collected from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) of the Ertych section (Fig. 1). Remarks.-Sinospirifer Grabau, 1931 is mainly known from the Famennian of China and East

European Platform [START_REF] Ma | Rugose corals and brachiopods across the Frasnian-Famennian boundary in central Hunan, South China[END_REF][START_REF] Ma | Revision of North American and selected Eurasian Late Devonian (Frasnian) species of Cyrtospirifer and Regelia (Brachiopoda)[END_REF]Ma and Day, 2007), but also from Western Europe [START_REF] Mottequin | Les Brachiopodes de la transition Frasnien/Famennien dans le Bassin de Namur-Dinant (Belgique). Systématique-Paléoécologie-Biostratigraphie Extinctions[END_REF]. Our material is assigned to the genus Sinospirifer rather than to Cyrtospirifer based on its central foramen or pedicle tube penetrating the pseudodeltidium, greatly thickened subsinal or extrasinal dental plates and the presence of delthyrial thickening formed by a development of strong apical callosity. Thus, this study establishes for the first time the presence of this genus within the Frasnian strata in Armenia.

Sinospirifer sp. 2

Plate 7.14-7.18; Figure 40 Occurrence.-The specimens were collected from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpensis Zone of Rzhonsnitskaya and Mamedov (2000) of the Ertych section (Fig. 1). Material.-Two partly exfoliated articulated specimens.

Remarks.-The greatly thickened and extrasinal dental plates, development of a strong apical callus in the ventral interior and unsupported ctenophoridium observed in our material suggests an assignment to the genus Sinospirifer [START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF]. However, the poor state of preservation and insufficiency of our material precludes the possibilities to reach a more confident identification until the species level. Sinospirifer sp. 2 seems to be very close to Sinospirifer sp. indet. 1 but differs from the latter by its more inflated and equibiconvex shell, extended cardinal extremities (although they are poorly preserved in the former), large number of ribs and by its unsupported ctenophoridium. However, further material is needed to compare these species more comprehensively.

Genus Pseudocyrtiopsis Ma and Day, 1999 Type species.-Cyrtiopsis spiriferoides [START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF].

Remarks.-Ma and Day (1999) created the genus Pseudocyrtiopsis to include those cyrtospiriferide species that resemble to some extent to Cyrtiopsis [START_REF] Grabau | Stratigraphy of China. Part 1. Palaeozoic and older: Geological Survey of China[END_REF], but differs from the latter due to wide hinge line and the presence of delthyrial plate. Although both Ma and Day (1999) and later [START_REF] Gourvennec | Spiriferida and Spiriferinida[END_REF] Occurrence.-This species is found only in the Ertych Regional Stage, which corresponds to the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957) and to the Cyrtiopsis orbelianus-Cyrtiopsis armenicus Zone of Rzhonsnitskaya and Mamedov (2000) (Fig. 3).

Description Etymology.-Areni is the name of the center of Areni Municipality of the Vayots Dzor Province, where the species was found.

Material.-Twenty-four articulated specimens and ten dissociated valves from the Ertych Regional Stage of the Ertych (ten articulated specimens and four ventral valves), Djravank (eleven articulated specimens and four ventral valves) and Noravank (three articulated specimens and two ventral valves) sections.

Shell ontogeny.-Although our material does not include juveniles, the examination of relatively small specimens (young stages of growth) show that the latter display all the external morphological characters also visible on the adults that are typical for this species. The size distributions during the growth, as represented by the width/length, the width/thickness, the width/width of sulcus and the width/length of dorsal valve plots, show a continuous and progressive growth with no distinct grouping (Fig. 42). The relative proportions of Pseudocyrtiopsis areniensis n. sp. represented by sufficient material remain constant (linear regression: y = ax+b; significant probability value: p < 0.001*** whatever the degree of development of individuals (Fig. 42)). Moreover, the correlation is positive with width varying proportionally with length, thickness, width of sulcus and the length of dorsal valve. To complete the scatter plots, the measurements (in mm) of numerous individuals of Pseudocyrtiopsis areniensis n. sp. are also presented in Remarks.-The external and internal features observed (e.g. rounded subpentagonal outline, wide hinge line, mucronate cardinal extremities, high and apsacline ventral interarea, the type of pseudodeltidium and micro-ornament, strong dental plates, well-developed delthyrial plate) in the studied specimens indicate affinities to genus Pseudocyrtiopsis Ma and Day, 1999, which has so far only been documented from China (Ma and Day, 1999) and dubiously from Belgium (Mottequin and Brice, 2019).

Pseudocyrtiopsis areniensis n. sp. may be distinguished from Pseudocyrtiopsis spiriferoides [START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF] as revised Ma and Day (1999), by its more inflated shell, higher tongue and the lack of primary sinal pairs of ribs that are much stronger than others.

The new species differs from Pseudocyrtiopsis kunlunensis (Wang and Zhu in [START_REF] Jin | Brachiopoda[END_REF]) by its more inflated, globular shell, high to very high, subcircular to subogival tongue and by the larger number of ribs on fold and in sulcus.

Genus Aramazdospirifer Serobyan et al.

See Serobyan et al. (in press)

Aramazdospirifer orbelianus (Abich, 1858) See Serobyan et al. (in press), Figs. 3456 Dorsal valve interior (Fig. 43) with flat to slightly concave, unsupported ctenophoridium composed of up to 27 well-developed relatively long lamellae; dental sockets shallow; hinge plate divided; crural bases mediodorsally oriented; spiral cones not preserved in the sectioned specimens.

Etymology.-The species name refers to Marina Semenovna Abrahamyan (1922Abrahamyan ( -1999)) relatively high ventral interarea, high tongue) can be observed since the early growth stages; the only difference to separate juveniles from adults is their shell size. The size distributions during the growth, as represented by the width/length, the width/thickness, the width/width of sulcus and the width/length of dorsal valve plots, show a continuous and progressive growth with no distinct grouping (Fig. 44). The relative proportions of the latter is represented by sufficient material remain constant (linear regression: y = ax+b; significant probability value: p < 0.01*** whatever the degree of development of individuals (Fig. 44)). Moreover, the correlation is positive with width varying proportionally with length, thickness, width of sulcus and the length of dorsal valve. However, the 123 length/width of the dorsal valve ratio shows less dispersed values (Fig. 44). To complete the scatter plots, the measurements (in mm) of numerous individuals of P. abrahamyanae n. gen., n. sp. are also represented in Table 8.

Remarks.-Despite the great faunal similarities between the Upper Devonian sequences of Armenia and Nakhichevan, the literature review of papers devoted to the brachiopods described in

Nakhichevan (e.g., Grechishnikova, 1986Grechishnikova, , 1996 Occurrence.-Frasnian of Armenia, Nakhichevan and Famennian of Kazakhstan.

Etymology.-Angustus, a, um (Latin): narrow; sulcus, i (Latin): furrow; spirifer is the usual ending for the spiriferides genera. The name draws attention to the narrow sulcus of the genus.

Remarks.-Angustisulcispirifer n. gen. is included in the Superfamily Cyrtospiriferoidea on account of its dental plates, delthyrial plate and ctenophoridium. Angustisulcispirifer n. gen. is assigned to the Family Cyrtospiriferidae, as defined by Johnson (2006), based on costate sulcus and fold. It is further placed within the Subfamily Cyrtospiriferinae as defined by [START_REF] Carter | A revised classification of the spiriferid brachiopods[END_REF] and Johnson (2006) due to its wide hinge line and mucronate cardinal extremities.

The new genus is distinguished externally from Cyrtospirifer Nalivkin in Frederiks, 1924, as revised by [START_REF] Ma | Revision of North American and selected Eurasian Late Devonian (Frasnian) species of Cyrtospirifer and Regelia (Brachiopoda)[END_REF], by its more globular, longitudinally elongated and inflated shell as well as poorly developed fold and sulcus. Internally, Angustisulcispirifer n. gen. differs by its short delthyrial plate and robust dental plates.

Angustisulcispirifer n. gen. resembles to some extent the genus Uchtospirifer Ljashenko, 1957 as revised by Sokiran (2006) Occurrence.-This species characterizes the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) (Fig. 3). Previously, it was reported from the Baghrsagh and Danzik sections in Nakhichevan and from the Noravank section in Armenia (Arakelyan, 1964) (Fig. 1).

Description.-Shell medium-to large-sized, wider than long, sharply ventribiconvex, rounded subpentagonal in outline, widest at hinge line, highest at midlength or more posteriorly; cardinal extremities mucronate; anterior margin flat to slightly emarginate; anterior commissure uniplicate.

Ventral valve strongly inflated, rounded pentagonal in outline, with convex flanks sloping steeply towards lateral commissures; highest in the posterior third of the valve, then progressively decreasing towards anterior margin; umbo strongly inflated, large and prominent; beak small, erect to incurved; interarea apsacline, moderately high, well-defined, concave; delthyrium wide, the type are also represented in Table 9. Remarks.-Although the biostratigraphic significance of Angustisulcispirifer arakelyani n. gen., n.

of
sp. has been known for a while, the latter was never illustrated and its internal characters were not examined so far. Moreover, A. arakelyani n. gen., n. sp. was mistakenly confused with Spirifer verneuili var. subarchiaci Martelli, 1902 (= Plicapustula subarchiaci [START_REF] Martelli | Il Devoniano superiore dello Schensi (Cina)[END_REF] sensu Ma and Day (2007)) from the middle Famennian of southeastern China, since Arakelyan (1952) used this taxon name until now. The Armenian material differs from Martelli's species by its more globular and inflated shell as well as by its poorly developed fold and sulcus. Internally, the new species is distinguished by its short delthyrial plate and strong dental plates.

Comparison with the other species.-Angustisulcispirifer arakelyani n. gen., n. sp. is very close to Uchtospirifer subarchiaci [START_REF] Martelli | Il Devoniano superiore dello Schensi (Cina)[END_REF] sensu Afanasjeva in Alekseeva et al. (2018b) from the Frasnian of Nakhichevan (e.g., subpentagonal shell outline, dorsibiconvex lateral profile, inflated umbones, ventral triangular and apsacline interarea, shallow sulcus and low fold, simple ribs on flanks, bifurcating in sulcus and on fold, the presence of a well-developed delthyrial plate and myophragm), which is also evidently confused with Martelli's species and needs to be reinvestigated. However, the Armenian material is distinguishable by its wide hinge line, higher ventral interarea and less inflated shell. It is worth noting that Afanasjeva in Alekseeva et al. Solkina in Sidjachenko (1962), but it also differs from them by its weakly developed fold and sulcus, very low tongue more or less rounded in outline, and by the presence of a stout and knoblike callosity developed in the ventral valve.

The re-examination of Arakelyan (1952Arakelyan ( , 1964) ) and Abrahamyan et al. (1973)'s material demonstrates that the species used to recognize the Frasnian strata in Armenia and Nakhichevan by these authors was A. arakelyani n. gen., n. sp. and not Uchtospirifer subarchiaci [START_REF] Martelli | Il Devoniano superiore dello Schensi (Cina)[END_REF] sensu Afanasjeva in Alekseeva et al. (2018b). Moreover, as we have never found the latter species in the recently collected fauna from Armenia we suggest using the new species to recognize the lower Frasnian in Armenia.

Subfamily Cyrtiopsinae [START_REF] Ivanova | Osnovnyye zakonomernosti evolyutsii spiriferid (Brachiopoda)[END_REF] Genus Tornatospirifer new genus Occurrence.-This species defines the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957), as well as the Cyrtiopsis orbelianus-Cyrtiopsis armenicus Zone of Rzhonsnitskaya and Mamedov (2000) (Fig. 3) both in Armenia and Nakhichevan. Formerly, T.

armenicus was documented from the Ertych Regional Stage of the Ertych, Noravank, Shamamidzor and Zangakatun sections in Armenia (Abrahamyan, 1957;Arakelyan, 1964) and from the Gyumushlug section in Nakhichevan (Abrahamyan, 1957;Grechishnikova, 1986) (Fig. 1).

Description Shell ontogeny.-The examination of juvenile forms suggests that the latter differ from adults in having inconspicuous umbones, small acute beaks, fainter ribs and flat ventral interarea. The tongue of specimens at young stages is subogival in outline, then progressively becoming subcircular with age. Sulcus and fold well-developed since early grow stage. The size distribution during the growth, as represented by the width/length, the width/thickness, the width/width of sulcus and the width/length of dorsal valve plots, shows a continuous and progressive growth with no distinct grouping (Fig. 48). The relative proportions of Tornatospirifer armenicus (Abrahamyan, 1974) represented by sufficient material remain constant (linear regression: y = ax+b; significant probability value: p < 0.01*** whatever the degree of development of individuals (Fig. 48)).

Moreover, the correlation is positive with width varying proportionally with length, thickness, width of sulcus and the length of dorsal valve. The length/width of the dorsal valve shows less dispersed values (Fig. 48). To complete the scatter plots, the measurements (in mm) of numerous individuals of Tornatospirifer armenicus (Abrahamyan, 1974) are also presented in Table 10. (Abrahamyan, 1974). Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

Remarks.- Arakelyan (1952) initially identified this species as 'Cyrtospirifer murchisonianus', a lower Frasnian representative of the genus Uchtospirifer from Russia [START_REF] Ljashenko | Atlas brakhiopod i stratigrafiya Devonskikh otlozhenii tsentral'nykh oblastei Russkoi Platformy[END_REF]Sartenaer, 1965b). It was first illustrated by Abrahamyan (1957), who also examined its internal morphology, without resolving the taxonomic confusion. Many years later, the relatively detailed study of Abrahamyan (1974) established that it should be assigned to the genus Cyrtiopsis and she considered it as a subspecies of Cyrtiopsis senceliae Sartenaer, 1956 (= 'Pseudocyrtiopsis' senceliae, see discussions in Ma and Day (1999) and Mottequin and Brice (2019)) known from the lower Famennian of southern Belgium, of which one of the paratypes (Sartenaer 1956: pl. 1, fig. 4) was re-illustrated recently by Mottequin and Brice (2019: fig. 5.16-20). In fact, 'P.' senceliae is clearly distinct from the Armenian material as its mucronate shell is longer than wide (different outline) and displays notably a fold divided longitudinally into three subequal parts. [START_REF] Brice | Le Dévonien de l'Elbourz oriental: stratigraphie, paléontologie (Brachiopodes et Bryozoaires)[END_REF] considered Cyrtiopsis senceliae armenica Abramyan, 1974 as a synonym of Ghorispirifer chakhaensis (Brice, 1971) known from the upper and uppermost Famennian of Afghanistan and Iran. However, as explained by Mottequin and Brice (2019), this statement cannot be accepted as the material from Armenia can be easily distinguished from G. chakhaensis by its outline (G. chakhaensis displays a rounded or ovate outline with rounded posterolateral commissures whereas the Armenian species displays rounded subpentagonal outline and almost straight posterolateral commissures), its pseudodeltidium formed by several distinct plates, its high ventral interarea, having more ribs in sulcus and on fold and lacking numerous pustules developed on capillae. Moreover, T. armenicus has a delthyrial plate, which is absent in G. chakhaensis.

Afterwards, Aristov et al. (1979) raised Abrahamyan's (1974) subspecies to the species level. Grechishnikova (1986) erected Cyrtiopsis caucasia from the lower Famennian of Nakhichevan and indicated the similarity to C. senceliae armenicus coming from the same locality (Gyumushlug section; Fig. 1). The author compared her material with Abrahamyan's (1974) subspecies and mentioned that C. caucasia differs from the former by its triangular shell outline, smaller size, ventral triangular interarea and prominent ventral beak. Grechishnikova (1986: pl. 1. fig. 3) illustrated only the holotype, which was re-illustrated by Afanasjeva in Alekseeva et al. (2018b: pl. 29, fig. 5). The latter compared Grechishnikova's species and C. senceliae from Western Europe, China [sic] as well as Armenia, and indicated that the former differs by its subtriangular shell outline. Thus, she implicitly considered either that Abrahamyan's (1974) subspecies is still a subspecies of [START_REF] Sartenaer | Signification et importance du genre Cyrtiopsis dans les dépôts Famenniens inferieurs. Deuxième note: Cyrtiopsis senceliae nov. sp[END_REF] species, or simply that she does not recognize armenicus as a valid subspecies. However, all of the external features mentioned by both Grechishnikova (1986) and Afanasjeva in Alekseeva et al. (2018b), which were supposed to point the differences, are also observed in Abrahamyan's species except the subtriangular shell outline that is not even observed in their material, as the holotype of C. caucasia is rounded subpentagonal in outline. Consequently, they certainly should be considered as intraspecific variations. Thus, we consider Cyrtiopsis caucasia as a junior synonym of Abrahamyan's species. As seen above, a great attention has been paid to this species because of its peculiar external morphology and potential utility for recognition the lower Famennian strata in the Lesser Caucasus; however its affinities at the genus level were unknown so far.

Diversity and stratigraphic distribution of brachiopods in the studied sections

The Upper Devonian succession in our 3 studied sections yielded abundant and diverse brachiopod fauna. The brachiopods were primarily collected from Intervals 1 and 4; the other 2 intervals are mainly composed of siliciclastic/shaly rocks and did not really yield any brachiopods. The examination of these brachiopod specimens, both externally and internally, led us to identify altogether twenty-six species (Fig. 49). In total, twenty-one brachiopod species are described in the Ertych section among which ten come from the Interval 1 and eleven from the Interval 4. More particularly, rhynchonellides are scarce in the Interval 1, as it contains only two species:

Cyphoterorhynchus koraghensis koraghensis (Reed, 1922) and Ripidiorhynchus gnishikensis (Abrahamyan, 1959), whereas they are more diverse and abundant in the Interval 4 and represented by four species: Sartenaerus baitalensis (Reed, 1922), Sartenaerus charakensis (Brice, 1967), Greira transcaucasica Erlanger, 1993 and Sharovaella? sp (Fig. 49). The atrypide brachiopods occur only in the Interval 1 (Fig. 49); they are represented by three species: Atryparia (Costatrypa)

ertichensis (Abrahamyan, 1959), Spinatrypa (Spinatrypa) sp. and Desquamatia (Seratrypa)

abramianae [START_REF] Komarov | Novye Desquamatia (Brachiopod) vidy iz devonskikh otlozheniy Zakavkaz[END_REF]. All three atrypide species appear not to be encountered above the layer Er19/4 and thus they occur only in the Interval 1 (Fig. 49). The Order Athyrida is represented by only one species Crinisarina pseudoglobularis Serobyan et al., 2021, which appears at the base of Interval 4 and then immediately becomes highly abundant. The abundance of this species decreased in the middle part of interval and again increased at the top (Fig. 49). In contrast to atrypide and athyride brachiopods, the spiriferides are relatively diverse both in the Interval 1 and Interval 4. In particular, the Interval 1 includes five species (Cyrtospiriferinae gen. et sp. 1, (Abrahamyan, 1974)). Thus, spiriferides are more diverse and rich in the Interval 4 than in the Interval 1 (Fig. 49). Additionally, it should be noted that none of the spiriferides of Interval 1 were traced above this interval (Fig. 49). The sedimentary sequences of the Djravank section bear similar brachiopod faunas as those of the Ertych section (Fig. 50). In general, twenty species are described in this section, six of which were recovered from the Interval 1 and fourteen from the Interval 4. Most notably, the Interval 1 of Djravank section includes those two rhynchonellides (Cyphoterorhynchus koraghensis koraghensis (Reed, 1922) and Ripidiorhynchus gnishikensis (Abrahamyan, 1959)), which are described at the base of the Ertych section. Regarding the Interval 4, in addition to those rhynchonellides (Sartenaerus baitalensis (Reed, 1922), Sartenaerus charakensis (Brice, 1967) and Greira transcaucasica Erlanger, 1993) (Reed, 1922), Sartenaerus charakensis (Brice, 1967), Greira transcaucasica Erlanger, 1993 and Porthmorhynchus? sp.). The Order Atrypida is represented by a single species (Desquamatia (Seratrypa) abramianae Komararov, 1992) in the Interval 1, as is the case of the Djravank section.

The spiriferides are also relatively scarce by only six species of which only one occurs in the Interval 1 and those 5 in the Interval 4 (Fig. 51). The species documented from these three sections belong to the orders Rhynchonellida, Atrypida, Athyrida and Spiriferida. Interestingly, none of the species of Interval 1 is documented also in the Interval 4 (Figs. 49-51).

Bio-and chronostratigraphy

The Devonian brachiopod assemblages are extensively applied in biostratigraphic correlations of shallow water successions in the Lesser Caucasus. However, the biostratigraphic framework of the Lesser Caucasus based on brachiopods still remains largely undocumented. This is probably due to the poorly constrained stratigraphic sections and the lack of standard biostratigraphic markers such as conodonts, which precludes detailed dating. The brachiopods recovered from our studied sections belong to two distinct assemblages (Fig. 52). The first assemblage is described in the Interval 1, which may be correlated with the assemblage of Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) as it contains several taxa that are typical for the latter zone (e.g., Ripidiorhynchus gnishikensis, Cyphoterorhynchus koraghensis koraghensis, Atryparia (Costatrypa) ertichensis). Rzhonsnitskaya and Mamedov (2000)'s zone is correlated with the transitans-punctata conodont zones. Consequently, it can be reasonably assumed that the brachiopod assembalge described from the Interval 1 also corresponds to the transitans-punctata conodont zones. However, neither Cyphoterorhynchus arpaensis (Abrahamyan, 1957) nor Cyrtospirifer subarchiaci sensu Rzhonsnitskaya and Mamedov (2000) (=Angustisulcispirifer subarchiaci [sic!]) was not revealed by the recent sampling in our sections.

Therefore, I suggest using Ripidiorhynchus gnishikensis and Angustisulcispirifer arakelyani n. gen., n. sp. for defining this biozone in Armenia, as the latter species are abundant and restricted in the Frasnian strata. Moreover, R. gnishikensis has been also described in Nakhichevan (Pakhnevich 2018 in Alekseeva et al., 2018a). Consequently, I thereby establish a new assemblage brachiopod zone, namely the Ripidiorhynchus gnishikensis-Angustisulcispirifer arakelyani that may be correlated with the transitans-punctata zones (Fig. 53). Biostratigraphically speaking, this biozone corresponds to the Baghrsagh Regional Stage of Arakelyan (1964) as the limestone layers, where the assemblage was found, include brachiopod species (e.g., Angustisulcispirifer arakelyani, Cyphoterorhynchus koraghensis koraghensis Atryparia (Costatrypa) ertichensis), which Arakelyan considered the most significant while establishing the latter horizon. The Intervals 2 and 3 are mostly composed of siliciclastic rocks and yielded a few poorly preserved rhynchonellids, which were impossible to identify. These intervals together appear to constitute the Noravank Regional

Stage. Only at the transition between the intervals 3 and 4, a rhynchonellide species Ripidiorhynchus djravankensis n. sp. is described, but it is impossible to speak about a biozone as this species is observed only in the Djravank section. The second brachiopod assemblage comes from the Interval 4 (Fig. 52), which is lower Famennian in age. First of all, it is worth to emphasize that there are different brachiopod biozones established for the lower Famennian (Fig. 53). More particularly, in the scheme of Abrahamyan (1957), the lower Famennian is characterized by the Cyrtospirifer orbelianus taxon-range Zone (Fig. 52). [START_REF] Grechishnikova | K biostratigrafii srednego Devona Zakavkaz'ya: Byulleten' Moskovskogo Obshchestva Ispytateley Prirody[END_REF] also recognized a single biozone within the lower Famennian interval, but termed it Mesoplica meisteri Zone. This scheme was further updated by Alekseeva et al. (2018a) and renamed the Cyrtospirifer asiaticus-Mesoplica meisteri Zone (Fig. 53). In contrast to these authors, Rzhonsnitskaya and Mamedov (2000) recognized two brachiopod biozones: the lowest Famennian Mesoplica meisteri-Cyrtospirifer asiaticus and the lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus zones (Fig. 53). The examination of the brachiopod assemblage from the Armenian sections shows that the lower Famennian is represented herein by only one biozone, which is devoid of Mesoplica meisteri [START_REF] Peetz | Beiträge zur Kenntniss der Fauna aus den devonischen Schichten am Rande des Steinkohlen-Bassins von Kusnetzk (West-Siberien): Saint-Pétersbourg[END_REF] [=Ardiviscus meisteri [START_REF] Peetz | Beiträge zur Kenntniss der Fauna aus den devonischen Schichten am Rande des Steinkohlen-Bassins von Kusnetzk (West-Siberien): Saint-Pétersbourg[END_REF]] and Cyrtospirifer asiaticus (Brice, 1971). Instead, it is highly rich in Aramazdospirifer orbelianus (Abich, 1858) and Tornatospirifer armenicus (Abrahamyan, 1974) species, both of which appear together within the same level: above the oncolitic grainstone layer (e.g., Er19/92, Nv17/4), wherein Ginter et al. ( 2011) described conodont elements indicating the crepida conodont Zone. Therefore, I propose to use both species for recognizing the lower Famennian strata (crepida Zone) in the Armenian sections, taking into account their taxonomic update. It is also worth to remind here that the crepida Zone is coeval to the Polygnathus brevilaminus-Icriodus cornutus conodont Zone of Aristov (1994). This biozone corresponds to the Ertych Regional Stage of Arakelyan (1964).

Diversity and assemblages of brachiopods across the F-F interval

The consequences of the Kellwasser Biocrisis on the brachiopods from the Lesser Caucasus and their post-crisis recovery remain largely undocumented until now. Moreover, in the absence of standard biostratigraphic markers such as conodonts, the precise location of the F-F boundary remains unclear. However, it is possible to assess the diversity of the brachiopods prior to this crisis and after it, on the basis of current results that are additionally complimented by published data (Fig. 54), keeping in mind that the conodont biozonation adopted herein dates back to Aristov (1994). Additionally, it is worth noting that only those occurrences are included, which are illustrated and/or further confirmed by other studies; however, some of them might need modern taxonomic reassessment. In this study, twenty-six brachiopod species are described from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000), which corresponds to the transitans-punctata conodont zones and from the lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus Zone of Rzhonsnitskaya and Mamedov (2000), equivalent to the Cyrtospirifer orbelianus Zone of Abrahamyan (1957). The latter biozone is correlated with the crepida conodont Zone. There are also twenty-six other species documented previously by Abrahamyan (1957Abrahamyan ( , 1974)), Arakelyan (1964) and Alekseeva et al. (2018a, b) from F-F interval, which were not found during our field trips. Up to now, all the described brachiopod species belong to the orders Orthotetida, Productida, Rhynchonellida, Atrypida, Athyrida and Spiriferida. More particularly, the only representative of the Order Orthotetida in the Lesser Caucasus was documented by Abrahamyan (1957) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone. It appears that Schuchertella sp. did not cross the F-F boundary (Fig. 54). Whereas the order Productida was more diverse with six species, of which two (Devonoproductus sp., Productella subaculeata [START_REF] Murchison | Description de quelques-unes des coquilles fossiles les plus abondantes dans les couches de´voniennes du Bas-Boulonnais[END_REF]) were described in the Frasnian before from the studies of Abrahamyan (1957Abrahamyan ( , 1974)), Arakelyan (1964) and Alekseeva et al. (2018a, b). Red color indicates the species that were unknown before this study.

and five species (Productella subaculeata [START_REF] Murchison | Description de quelques-unes des coquilles fossiles les plus abondantes dans les couches de´voniennes du Bas-Boulonnais[END_REF], Productella herminae Frech, 1891, Productella? sp., Ardiviscus meristeri [START_REF] Peetz | Beiträge zur Kenntniss der Fauna aus den devonischen Schichten am Rande des Steinkohlen-Bassins von Kusnetzk (West-Siberien): Saint-Pétersbourg[END_REF] and Hamlingella ? murchisoniana (de Koninck, 1847)) sensu Abrahamyan (1974) in the lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus Zone; Productella subaculeata [START_REF] Murchison | Description de quelques-unes des coquilles fossiles les plus abondantes dans les couches de´voniennes du Bas-Boulonnais[END_REF] appears to overcome the F-F boundary successfully (Fig. 54). Two rhynchonellide species Cyphoterorhynchus koraghensis koraghensis (Reed, 1922) and Ripidiorhynchus gnishikensis (Abrahamyan, 1959) are described in this study from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in addition to Cyphoterorhynchus arpaensis (Abrahamyan, 1957) and Porthmorhynchus ferquensis (Gosselet, 1887), which were described previously by Abrahamyan (1957) and Pakhnevich in Alekseeva et al. (2018a). Therefore, it appears that the rhynchonellides are represented by only two subfamilies Trigonirhynchiinae and Ripidiorhynchinae in the Frasnian of the Lesser Caucasus. Although, R. gnishikensis disappeared in the Frasnian, the genus evidently crossed the F-F boundary in the Armenian sections and was represented in the lower Famennian by R. djravankensis n. sp., which apparently originated from the former species.

In spite of a low diversity of rhynchonellides in the Frasnian, the lower Famennian marks a comparably high diversity, where the latter became one of the dominant groups with eleven species.

Most notably, R. djravankensis n. sp. is described within the Noravank Regional Stage, while the other ten species come from the Ertych Regional Stage, which is correlated with the orbelianus Zone. This assemblage includes three species (Sartenaerus baitalensis (Reed, 1922), S. charakensis (Brice, 1967) and S. letiensis (Gosselet, 1887)) belonging to the Famennian genus Sartenaerus

Özdikmen, 2008, one species (Ptychomaletoechia sp.) to the Famennian-Tournaisian genus Ptychomaletoechia Sartenaer, 1961 and two species (Porthmorhynchus ferquensis (Gosselet, 1887 and Porthmorhynchus? sp.) refer to Porthmorhynchus Sartenaer, 2001, which is mainly known from the middle-upper Frasnian. These genera are included in the Subfamily Trigonirhynchiinae.

The subfamilies Ripidiorhynchinae and Greirinae here consist of two genera (Fig. 55), of which the indicates species which are known from Armenia based on the data of Abrahamyan (1957Abrahamyan ( , 1974) ) and Arakelyan (1964); blue color indicates species reported from Nakhichevan (Alekseeva et al., 2018a, b); black color points those species that are known both from Armenia and Nakhichevan. Abrahamyan (1957Abrahamyan ( , 1974) ) and Arakelyan (1964); blue color indicates species reported from Nakhichevan (Alekseeva et al., 2018a, b); black color points those species that are known both from Armenia and Nakhichevan.

former includes Paropamisorhynchus Sartenaer, 2001 andGesoriacorostrum Sartenaer, 2003 that are represented by three species (Paropamisorhynchus kotalensis (Brice, 1971), Gesoriacorostrum boloniense (Orbigny, 1850) and Gesoriacorostrum? sp.), while the latter comprises of Greira Erlanger, 1993 andSharovaella Pakhnevich, 2012 that also include three species (Greira transcaucasica Erlanger, 1993, Sharovaella mirabilis Pakhnevich, 2012 andSharovaella? sp.).

Thus, it can be inferred that in the Lesser Caucasus, the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone is represented by only two rhynchonellide genera, whereas the lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus Zone in addition to the genus Ripidiorhynchus, which crossed the F-F boundary, also includes seven genera (Fig. 5455).

Six representatives of the Order Atrypida are documented from the Frasnian strata of the Lesser Caucasus, of which all vanished near the F-F boundary (Fig. 56). These species are allocated to Atryparia (Costatrypa), Spinatrypa (Spinatrypa), Desquamatia (Seratrypa) genera/subgenera, which in turn belong to the subfamilies Atrypinae, Spinatrypinae and Variatrypinae. It is also worth noting that [START_REF] Komarov | Devonskie atripidy Zakavkaz[END_REF], who in his groundbreaking monograph dealt exclusively with atrypides of the Lesser Caucasus, described eighteen atrypides in the Eifelian, twelve within the Givetian and only six in the lower Frasnian. This signifies that the depletion of atrypides diversity in the Lesser Caucasus commenced since the Givetian and continued in the course of the Frasnian and the diversity of atrypides was already low near the F-F boundary.

Crinisarina pseudoglobularis [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF] records the earliest history of the Order Athyrida in the Lesser Caucasus. This species appeared in the lower Famennian Ertych Regional

Stage and became extremely abundant within a short stratigraphic interval.

In contrast to atrypides and athyrides, the spiriferides were present both in the Frasnian and in the lower Famennian strata (Figs. 54,56). Moreover, they are the most diverse and abundant group of the Frasnian-lower Famennian interval with twenty-two species, of which ten are from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone and twelve species are described from the lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus Zone. Among the Frasnian species, only Cyrtospirifer verneuili [START_REF] Murchison | Description de quelques-unes des coquilles fossiles les plus abondantes dans les couches de´voniennes du Bas-Boulonnais[END_REF] sensu Abrahamyan (1957) seems to cross the F-F boundary; however, the occurrence of this species must be further confirmed by recent sampling. The Frasnian species, which were identified until the species level, belong to the genera Cyrtospirifer Nalivkin in Fredericks, 1924, Sinospirifer Grabau, 1931 and Angustisulcispirifer n. gen., which in their turn are allocated to the Subfamily Cyrtospiriferinae.

Thus, although the diversity of cyrtospiriferids was relatively high at the species level, it was quite low at the genus and subfamily levels. The spiriferides of the lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus Zone belong to Cyrtospirifer Nalivkin in Fredericks, 1924, Pseudocyrtiopsis Ma andDay, 1999, Aramazdospirifer n. gen., Pentagonaspirifer n. gen. and Tornatospirifer n. gen. With an exception of the latter genus, which is assigned to the Subfamily Cyrtiopsinae, all the lower Famennian genera are included in the Subfamily Cyrtospiriferinae. It is evident that the diversity of spiriferides was higher in the lower Famennian not only at the species level but also at the genus and subfamilies levels.

As highlighted above, a major turnover is observed among the orders Orthotetida, Productida, Rhynchonellida, Atrypida, Athyrida and Spiriferida at the transition between the Frasnian Baghrsagh and the lower Famennian Ertych regional stages , since twentyone species went extinct and only one productide and one spiriferide species seem to cross the F-F boundary and moreover their occurrences in the lower Famennian strata need to be confirmed. This drop of diversity is regarded as the record of the Kellwasser Biocrisis in the Lesser Caucasus.

Although, all clades were severely affected by the F-F Biocrises, the post-crisis diversification of productides, rhynchonellides and spiriferides appears to be quick in the course of the lower Famennian, which marks the appearance of two species within the Noravank Regional Stage and twenty-five in the Ertych Regional Stage. This is not the case of the Order Athyrida as only one single athyride species originated within the Ertych Regional Stage. However, it is worth to emphasize that at this stage, it is difficult to determine whether the Frasnian brachiopods includes twenty-three species, among which the spiriferides predominate, accounting for 48 % (11 species) of the total number of species, while the atrypides account for 26 % (6 species), rhynchonellides 13 % (3), prudoctides 9 % (2 species) and orthotetides only 4 % (1 species) (Fig.

57.1). The lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus assemblage includes

twenty-nine species belonging to the orders Productida, Rhynchonellida, Spiriferida and Athyrida (Fig. 57.2). The latter assemblage is dominated by the spiriferides and rhynconellides, accounting for 41 % (12 species) and 38 % (11 species) of the total number of species, respectively. At the same time, the productides make up 17 % (5 species) and the athyrides only 4 % (1 species).

Brachiopod encrustation patterns

Paleozoic encrusters were common elements of shelly substrates during the Devonian time. More particularly, as noted by [START_REF] Musabelliu | Patterns of cornulitid encrustation on the Late Devonian brachiopod shells from Russia[END_REF] the lower Famennian marked an increase of cornulitid abundance and morphological disparity. These epifaunal suspension feeders may be helpful for palecological interpretations as being fully marine, they were very sensitive to water salinity and inhabited only in water of normal salinity [START_REF] Vinn | Cornulitids from the Upper Devonian of the Central Devonian Field[END_REF] as it is also the case of most brachiopod species. However, their biological affinities, morphological peculiarities, paleobiodiversity remain largely undocumented. In our material, one of the brachiopod specimens (IGSNASRAGM 3965/PS 3071) belonging to Pentagonospirifer abrahamyanae n. gen., n. sp. is encrusted by two cornulitid tubeworms at its dorsal valve, near the anterior margin, though one of them is only partly preserved (Pl. 9.2, 9.19). The latter resembles the external features of the genus Cornulites Schlotheim, 1820, which representatives are considered as hard-substrate encrusters and known from the Middle Ordovician to the Upper Carboniferous [START_REF] Vinn | Adaptive strategies in the evolution of encrusting tentaculitoid tubeworms[END_REF]. The tube of ?Cornulites sp. is oriented with its aperture directed towards the brachiopod anterior commissure suggesting attachment to living shell and subsequent growth for "stealing" some food from currents, produced by the feeding activity of the brachiopod host (Richards, 1974). Moreover, the shell of this brachiopod displays distinct shell malformations caused by cornulitid growth affecting the host's shell-secreting epithelium. Obviously, feeding on the food brought by the currents produced by the lophophores of this brachiopod, this cornulitid species had a clear negative effect on the brachiopods, such as a deviation in the growth of its shell. It is likely that the small size of this brachiopod is due to the negative effects of these encrustors, and not related to age. In this regard, it is reasonable to consider this cornulitid species as an ectoparasite and not as a commensal in relation to its owner. This is also the case of cornulitids observed on one of the specimen of Cyrtopspirifer pseudoasiaticus n. sp. (IGSNASRAGM 3951/PS 3057; Pl. 6.18), though they are only partially preserved. The encrusters observed on the second specimen of Pentagonospirifer

Paleobiogeography

Although a precise paleolatitudinal evaluation of the Late Devonian position of the South Armenian Block is still hampered due to the remagnetization of Upper Paleozoic rocks following the Late Cretaceous obduction of ophiolites (Meijers et al., 2015), existing paleogeographic reconstructions place the SAB at the junction between the Iranian terranes (to the east) and the Anatolide-Tauride microplate (to the west). It was thus an integral part of the northern passive margin of Gondwana, facing the Paleotethys ocean to the north . Thus, during the Late Devonian it was part of a huge platform that was positioned within the southern hemisphere tropical carbonate development zone (Brock and Yazdi, 2000). The SAB was later individualized during the Triassic, as an independent microcontinent, as it migrated northwards following the opening of Neotethys further to the south (Sosson et al., 2010). However, some authors consider that during the Mesozoic, the SAB had the same kinematic trajectory as the Tauride plate and therefore it was part of it [START_REF] Rolland | The East Anatolia-Lesser Caucasus ophiolite: An exceptional case of large-scale obduction, synthesis of data and numerical modelling[END_REF].

The taxonomic assessment of brachiopods collected from the Frasnian-lower Famennian interval cropping out in the Ertych, Djravank and Noravank sections of Central Armenia allows us to recognize the presence of nine rhynchonellide, three atrypide, one athyride and thirteen spiriferide species. As rhynchonelliform brachiopods have a benthic mode of life and produce lecithotrophic larvae, their paleobiogeographic patterns have the potential to reveal past geographic boundaries and oceanographic connections, although caution should be exercised on questions of taxonomic consistency, comparison of assemblages of similar age and biofacies (Brock and Yazdi, 2000). In that respect the two species of the Famennian genus Sartenaerus found in the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957) (S. baitalensis and S. charakensis) are of particular paleobiogeographic significance as they point to a likely wide Frasnian-lower Famennian brachiopod bioprovince developed along the northern Gondwana margin, from the SAB to Afghanistan and Pamir (Fig. 58). However, it should be stressed that in spite of the In this study, two species of Ripidiorhynchus genus are described, R. gnishikensis (Abrahamyan, 1959) from the Frasnian and R.djravankensis n. sp., from the lower Famennian, of which the latter was probably originated from the former as both species share several common superficial and internal features. [START_REF] Racki | Evolution of the bank to reef complex in the Devonian of the Holy Cross Mountains[END_REF] from the Armenian sections. It is also worth stressing that the genus is known so far only from the Frasnian, as its type species P. ferquensis is known from the middle-upper Frasnian of northern France (Boulonnais region) and Nakhichevan (Pakhnevich in Alekseeva et al., 2018a). The other species assigned to this genus (P. elburzensis) is known from the upper Frasnian of the Alborz Mts (northern Iran; [START_REF] Gaetani | Brachiopods and mollusks from Geirud Formation, Member A (Upper Devonian and Tournaisian): The geology of the Upper Djadjerud and Lar Valleys (North Iran): 2[END_REF]). Thus, the doubtful report of this genus from the lower Famennian Cyrtospirifer orbelianus Zone of Armenia is significant, although it requires further study to confirm its presence. Greira transcaucasica is one of the oldest punctate rhynchonellide species and, as it is only known from the SAB, this may represent an interesting case of endemicity.

The atrypide brachiopods display a high level of endemicity at the species level, since among the three described species, two (Atryparia (Costatrypa) ertichensis (Abrahamyan, 1959), Desquamatia (Seratrypa) abramianae [START_REF] Komarov | Novye Desquamatia (Brachiopod) vidy iz devonskikh otlozheniy Zakavkaz[END_REF] seem to be restricted to the SAB. However, the genera/subgenera (Atryparia (Costatrypa), Spinatrypa (Spinatrypa), Desquamatia (Seratrypa)) that include these three described species are known worldwide. The single athyride species recognized (Crinisarina pseudoglobularis [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF] represents also the first ever report of genus Crinisarina in the SAB and indeed in the entire northern margin of Gondwana, although it cannot be excluded that Crinisarina representatives are present in the Famennian of North Africa (Algeria and Morocco), where taxonomical studies have been mostly dedicated to the rhynchonellides, productidines and spiriferides, whereas the other elements of the brachiopod faunas received scant attention (see references in Mottequin et al., 2015). Alike other species of Crinisarina (see discussion [START_REF] Mottequin | Late middle Frasnian to early Famennian (Late Devonian) strophomenid, orthotetid and athyridid brachiopods from southern Belgium[END_REF], it is likely that C. pseudoglobularis Serobyan et al., 2021 had a preference for soft substrates, comprised of argillaceous sediments, on which it was attached with a thin pedicle. This corresponds well to our own observations, as this species was found mainly in shaly intervals. If among the rhynchonellides some species were described in other parts of the Gondwanan northern margin, the spiriferides display low level of cosmopolitanism and might be significant for the paleobiogeography only at the genus level. More particularly, in addition to type species, which appear to be endemic in the SAB, the newly described lower Famennian genera North America, but it appears that the latter genus was already present in the Frasnian.

1. The examination of the Frasnian-Famennian sedimentary sequences in Central Armenia revealed that the 'formations' established by Arakelyan (1964) have very similar lithological characteristics and that they cannot be distinguished without knowledge of their brachiopod assemblages; thus, they have a biostratigraphic rather than lithostratigraphic significance.

The four intervals introduced in the present study may serve as a basis for future establishment of more formal lithostratigraphic formations, useful for mapping purposes. and may be correlated with the Ertych Regional Stage. Aramazdospirifer and Tornatospirifer include two of the most biostratigraphically important species of the lower Famennian in the Lesser Caucasus, Aramazdospirifer orbelianus (Abich, 1858) and Tornatospirifer senceliae armenica (Abrahamyan, 1974), respectively.

5. The examination of brachiopod assemblages confirms the presence of a number of species known previously (e.g., Sartenaerus baitalensis, Ripidiorhynchus gnishikensis, Spirifer orbelianus, Cyrtiopsis senceliae armenica) from the South Armenian Block. However, I here provide for the first time a detailed description of the internal structure of Sartenaerus baitalensis, which is the type species of a biostratigraphically and paleogeographically important genus. Thus, the brachiopod record from Armenia firmly establishes the presence of the Famennian genus Sartenaerus in the lower Famennian (it was previously known since the middle Famennian; Mottequin et al., 2014). It is also the first documentation of S. charakensis in the Armenian sections; moreover, its stratigraphic range is extended here down to the Cyrtospirifer orbelianus Zone (it was previously known from the ghorensispamiricus Zone). Two species belonging to the genus Ripidiorhynchus Sartenaer, 1966a are described: R. gnishikensis (Abrahamyan, 1959) and R. djravankensis n. sp., the latter establishes the first record of this genus within the lower Famennian of the SAB. This study also documents for the first time the presence of the subgenera Atryparia (Costatrypa)

Copper, 1973 and Spinatrypa (Spinatrypa) [START_REF] Stainbrook | Substitution for the preoccupied name Hystricina[END_REF] Frasnian of the SAB.

The athyride species (Crinisarina pseudoglobularis [START_REF] Serobyan | Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block[END_REF] represents the first report of the genus Crinisarina in the SAB and indeed in the entire north Gondwanan realm. Remarkably, the genus Sinospirifer [START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF], which was previously known from the Famennian of China, East European Platform [START_REF] Ma | Rugose corals and brachiopods across the Frasnian-Famennian boundary in central Hunan, South China[END_REF][START_REF] Ma | Revision of North American and selected Eurasian Late Devonian (Frasnian) species of Cyrtospirifer and Regelia (Brachiopoda)[END_REF]Ma and Day, 2007) and Western Europe [START_REF] Mottequin | Les Brachiopodes de la transition Frasnien/Famennien dans le Bassin de Namur-Dinant (Belgique). Systématique-Paléoécologie-Biostratigraphie Extinctions[END_REF], is reported here since the Frasnian. Its paleobiogeographic distribution is thus wider than previously thoughtIt is likely that in addition to their type species, the newly erected genera Aramazdospirifer, Pentagonaspirifer, Angustisulcispirifer and Tornatospirifer include several other Famennian species described from Pamir (Tajikistan), Central Kazakhstan and the East European Platform, although the latter species are in need of a modern taxonomic reassessment. The paleobiogeographic distribution of the rhynchonellides, atrypides, spiriferides and athyrides within the Frasnian-lower Famennian sequences of Armenia suggests that the brachiopod communities thriving on the shallow water carbonate platform of the SAB included also species that were common to other parts of the Gondwanan northern margin extending eastwards to Afghanistan and Pamir, but also some apparently endemic species (e.g., R.

gnishikensis, R. djravankensis, G. transcaucasica, Aramazdospirifer orbelianus, Pentagonospirifer abrahamyanae).

6. A comparison between the brachiopod assemblages recorded in the Intervals 1 (Baghrsagh Regional Stage) and 4 (Ertych Regional Stage) reveals some interesting differences in diversity and assemblages structure. The assemblages are very different. More particularly, the rhynchonellides, atrypides and spiriferides species assemblages are very different, as with the exception of Cyrtospirifer verneuilli [START_REF] Murchison | Description de quelques-unes des coquilles fossiles les plus abondantes dans les couches de´voniennes du Bas-Boulonnais[END_REF]) sensu Abrahamyan (1957), none of the Frasnian species crossed the Frasnian-Famennian boundary. However, the early Famennian diversification of the productides, rhynchonellides and spiriferides appears to be high in the Armenian fossil record, which is not the case of athyrides as only one species is observed within the lower Famennian.

Paleontological plates Plate 1

Ripidiorhynchus gnishikensis (Abrahamyan, 1959) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(1-5). IGSNASRAGM 3927/PS 3033 (Djravank section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views.

Ripidiorhynchus djravankensis n. sp. from the lowest Famennian Noravank Regional Stage of Djravank section in Armenia.

(6-10). IGSNASRAGM 3929/PS 3035, almost complete juvenile specimen in ventral, dorsal, lateral, posterior, and anterior views.

(11-15). IGSNASRAGM 3930/PS 3036, partly exfoliated specimen in ventral, dorsal, lateral, posterior and anterior views.

(16-20). IGSNASRAGM 3931/PS 3037, almost complete specimen in ventral, dorsal, lateral, posterior and anterior views. Scale bar: 5 mm.

Plate 2

Cyphoterorhynchus koraghensis koraghensis (Reed, 1922) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(1-5). IGSNASRAGM 3933/PS 3039 (Ertych section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views.

(6-10). IGSNASRAGM 3934/PS 3040 (Djravank), partly exfoliated specimen in ventral, dorsal, lateral, posterior and anterior views.

(11-15). IGSNASRAGM 3935/PS 3041 (Djravank section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views. Scale bar: 5 mm.

Plate 3

Atryparia (Costatrypa) ertichensis (Abrahamyan, 1959) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(1-7). IGSNASRAGM 3936/AB270/3-54 (paralectotype, Ertych section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views (1-5), close-up of ornament

showing the bifurcation on the ventral valve (6), and Abrahamyan's original handwritten mark on the dorsal valve of the specimen (7). Scale bars: 10 mm (1-5), 2 mm (6).

Spinatrypa (Spinatrypa) sp. from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(8-13). IGSNASRAGM 3937/PS 3043 (Ertych section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views (21-25), and close-up to the micro-ornament displaying the growth lines covered by concentric microlines (26). Scale bars: 10 mm (8-12), 2 mm (13).

Plate 4

Desquamatia (Seratrypa) abramianae Alekseeva et Komararov, 1992 from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(1-5). IGSNASRAGM 3939/PS 3045 (Noravank section), partly corroded juvenile specimen in ventral, dorsal, lateral, posterior and anterior views. Plate 5

Cyrtospiriferinae gen. et sp. 1 from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchusarpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(1-6). IGSNASRAGM 3942/PS 3048 (Ertych section), partly corroded specimen in ventral, dorsal, lateral, posterior and anterior views (1-5), and close-up of the ornament displaying the poorly preserved ribs near at the front (6).

Cyrtospiriferinae gen. et sp. 2 from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(7-9). IGSNASRAGM 3943/PS 3049 (Djravank section), incomplete ventral valve in orthogonal and lateral views (7-8), and close-up of the ornament showing the ribs in the sulcus (9).

Cyrtospirifer? sp. 1 from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis

Zone of Rzhonsnitskaya and Mamedov (2000) in Armenia.

(10-11). IGSNASRAGM 3944/PS 3050 (Ertych section), incomplete ventral valve in orthogonal and posterior views.

Cyrtospirifer? sp. 2 from the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957) in Armenia. [START_REF]which is not the case of the new genus. The new genus is distinguished from the Famennian genus Dmitria Sidjachenko, 1961, by its well-developed sulcus and fold, its high and subogival tongue, its high ventral interarea and by the presence of numerous pustules developed on capillae. Internally, Tornatospirifer n. gen. mainly differs by its delthyrial plate, which[END_REF](13)(14)(15)(16). IGSNASRAGM 3946/PS 3052 (Djravank section), corroded specimen in ventral, dorsal, lateral, posterior and anterior views.

Cyrtospirifer sp. 1 from the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957) in Armenia.

(17-21). IGSNASRAGM 3948/PS 3054 (Djravank section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views. Scale bars: 10 mm (1-5, 7-8, 10-21), 2 mm (9), 0.5 mm (6).

Plate 6

Cyrtospirifer pseudoasiaticus n. sp. from the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957) in Armenia.

(1-5, 17). IGSNASRAGM 3950/PS 3056 (Djravank section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views (1-5), and close-up of the micro-ornament (capillae developed both on ribs and in interspaces).

(6-10, 18). IGSNASRAGM 3951/PS 3057 (Djravank section), corroded specimen in ventral, dorsal, lateral, posterior and anterior views (6-10), and oblique anterior view showing a partially preserved cornulitid tubeworm on the ventral valve ( 18).

Plate 7

Sinospirifer sp. 1 from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000).

(1-6). IGSNASRAGM 3955/PS 3061 (Ertych section), corroded specimen in ventral, dorsal, lateral, posterior, posterodorsal and anterior views.

(7-13). IGSNASRAGM 3956/PS 3062 (Djravank section), almost complete specimen in ventral, dorsal, lateral, posterior, posterolateral and anterior views (7-12), and close-up of the ventral interarea showing the partly preserved central foramen (13).

Sinospirifer sp. 2 from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000). (14)(15)(16)(17)(18). IGSNASRAGM 3958/PS 3064 (Ertych section), corroded specimen in ventral, dorsal, lateral, posterior and anterior views. Scale bars: 10 mm (1-12, 14-18), 0.5 mm (13).

Plate 8

Pseudocyrtiopsis areniensis n. sp. from the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957).

(1-9). IGSNASRAGM 3960/PS 3066 (Djravank section), almost complete specimen in ventral, dorsal, lateral, posterior, posterodorsal and anterior views (1-6), and close-up of the ventral interior

showing the pseudodeltidium (7-8) as well as close-up of the micro-ornament displaying capillae and tubercles deeloped both on ribs and in interspaces ( 9).

(9-14). IGSNASRAGM 3961/PS 3067 (Djravank section), corroded specimen in ventral, dorsal, lateral, posterior, posterodorsal and anterior views.

(15-20). IGSNASRAGM 3962/PS 3068 (Ertych section), corroded specimen in ventral, dorsal, lateral, posterior, posterodorsal and anterior views.

(21-26). IGSNASRAGM 3963/PS 3069 (holotype, Djravank section),corroded specimen in ventral, dorsal, lateral, posterior, posterodorsal and anterior views. Scal bars: 10 mm (1-6, 10-27), 2 mm (7-8), 1 mm (9).

Plate 10

Angustisulcispirifer arakelyani n. gen., n. sp. from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000), Armenia. The arrows indicate the anterior margin.

(1-6). IGSNASRAGM 3970/PS 3076 (Djravank section), partly exfoliated juvenile specimen in ventral, oblique ventral, dorsal, lateral, posterior and anterior views.

(7-12). IGSNASRAGM 3971/PS 3077 (holotype, Noravank section), almost complete specimen in ventral, dorsal, lateral, posterior, posterdorsal and anterior views.

(13-18). IGSNASRAGM 3972/AR 3078 (Ertych section), partly exfoliated specimen in ventral, dorsal, lateral, posterior, posterodorsal and anterior views. 1 Institute of Geological Sciences of the National Academy of Sciences of the Republic of Armenia-Yerevan, Armenia, 24A, Marshal Baghramyan Avenue, Yerevan 0019, Republic of Armenia <vahramserobyan@gmail.com> <aragrigoryan@yandex.ru> 2 Univ. Lille, CNRS, UMR 8198-Evo-Eco-Paleo, F-59000 Lille, France <vahram.serobyan@univ-lille.fr> <taniel.danelian@univ-lille.fr> <catherine.cronier@univ-lille.fr> Abstract.-The lower Famennian orbelianus brachiopod Zone established in Armenia by Abrahamyan (1957) (coeval to the crepida conodont Zone) contains an abundant and diverse brachiopod fauna that still remains poorly studied. In an effort to revise and update its systematic classification and to assess the brachiopod diversity after the Kellwasser extinction event in this area, our attention is here focused on rhynchonellides and athyridides. Six rhynchonellide species are described belonging to five genera as well as a single athyridide species (Crinisarina

F o r R e v i e w O n l y
pseudoglobularis sp. nov.), which is new to science. The genus Crinisarina is reported for the first time in the South-Armenian Block (SAB), which was then part of the northern margin of Gondwana. Some of the rhynchonellide species identified were previously recognized in this area but they required modern documentation and taxonomic reassessment. More particularly, it is the first time that the internal structure of Sartenaerus baitalensis (Reed, 1922) is here illustrated, taking into account that it is the type species of a biostratigraphically significant Famennian genus. One of the oldest punctate rhynchonellide species Greira transcaucasica Erlanger, 1993 is described and its intraspecific variability is documented quantitatively. From the paleogeographic viewpoint, the studied brachiopod fauna clearly shares affinities with contemporaneous ones from other regions of the Gondwanan northern margin that extends eastwards of the SAB to Afghanistan and Pamir, although there are also some endemic elements.

Introduction

The Upper Devonian sequences of the Lesser Caucasus (or Transcaucasia, Fig. 1) are remarkable in terms of their completeness and richness in fossil remains (Abrahamyan, 1957(Abrahamyan, , 1964;;Arakelyan, 1964;Alekseeva et al., 2018a, b). They have attracted the interest of pioneer geologists such as the famous German geologist Hermann Abich, who first described in 1858

Devonian outcrops and a new spiriferide species from Armenia, 'Spirifer' orbelianus. In Armenia, Upper Devonian-Lower Carboniferous brachiopods were systematically studied by

Abrahamyan during the years 1949 to 1974. One of her most important publications dates back to 1957 in which she described and illustrated 36 brachiopod species (including eight new ones) from the Famennian-Tournaisian interval. These species belong to the orders Athyridida,

F o r R e v i e w O n l y
Orthida, Orthotetida, Productida, Rhynchonellida and Spiriferida. In the same publication she also presented a biostratigraphic scheme based on brachiopods wherein part of the lower Famennian was characterized by the orbelianus taxon-range Zone (Fig. 2). The latter brachiopods were partly revised by Abrahamyan (1974) in addition to newly studied Frasnian species. However, despite the extensive taxonomic studies led by Abrahamyan (1957Abrahamyan ( , 1974) ) and more recently by Alekseeva et al. (2018a, b), who mainly focused on brachiopods from Nakhichevan (Azerbaijan), lower Famennian brachiopod assemblages from Armenia still remain poorly understood from the taxonomical and biostratigraphical points of view. This is especially true for the athyridide and rhynchonellide brachiopods, which are very common in the Upper Devonian-Lower Carboniferous sequences of this area, and their study can provide valuable insights into Late Devonian changes in brachiopod diversity and palaeobiogeographic distribution. Thus, the purpose of this paper is to re-investigate and to describe those present in the lower Famennian orbelianus Zone on the basis of newly collected material from three distinct localities in central Armenia (Fig. 1). Furthermore, their biostratigraphic and paleobiogeographic significance are also discussed.

Geological setting

The Upper Devonian sequences of Armenia are composed of mixed carbonate-siliciclastic sediments that accumulated on a shallow water platform. They consist essentially of marly and sandy biogenic limestones, rich in brachiopods, and intercalations of quartzites and shales.

Geodynamically speaking, they are part of the South-Armenian Block, a Gondwana-derived microcontinent that was detached and individualized during the Triassic and Jurassic ( Abrahamyan (1964) and Arakelyan (1964) into a number of horizons (e.g. Baghrsagh, Noravank, Ertych, Fig. 2) that are difficult to be recognized exclusively on the basis of their facies as they are partly defined on their brachiopod content.

Consequently, they have a biostratigraphic rather than lithostratigraphic significance (see Serobyan et al., 2019). Thus, because of their abundance in these sequences, brachiopods were recognized to be useful for stratigraphic correlations and used to support the extensive mapping effort planned for the area after the World War II. At the time, Armenia and Nakhichevan (Azerbaijan) were part of the USSR. [START_REF] Rzhonsnitskaya | Devonskiye otlozheniya Zakavkaz[END_REF] first established a Devonian biostratigraphical scheme based on brachiopods. This was a rudimentary zonal scheme that was much improved by Abrahamyan (1957), who introduced a continuous biozonation characterized by marker species or species assemblages (Fig. 2). The 'Cyrtospirifer' orbelianus Zone of Abrahamyan (1957) is a taxon-range biozone covering part of the Lower Famennian. Grechishnikova et al. (1982) and Rzhonsnitskaya and Mamedov (2000) applied Abrahamyan's zonal scheme in Nakhichevan, by improving and complementing it for some intervals. A subsequent step forward was achieved by the integration of this brachiopod zonation with the conodont study carried out by Aristov (1994) in Nakhichevan. Figure 2 correlates the above mentioned brachiopod zones with the regional conodont zonation of Aristov (1994) established in Nakhichevan and the standard conodont zonation of [START_REF] Ziegler | The Late Devonian standard conodont zonation[END_REF].

Materials and Methods

F

o r R e v i e w O n l y
The bulk of specimens illustrated and investigated herein was collected during several field seasons organized in 2018 and 2019. The material was collected from the 'Cyrtospirifer' orbelianus Zone of Abrahamyan (1957) as the latter crops out well in three distinct sections of central Armenia (Ertych, Djravank and Noravank; Fig. 1). It can be correlated with the 'Cyrtiopsis' orbelianus-'Cyrtiopsis' armenicus Zone of Rzhonsnitskaya and Mamedov (2000) and considered as coeval to the crepida standard conodont Zone of [START_REF] Ziegler | The Late Devonian standard conodont zonation[END_REF].

The material sampled by our care in the field was complemented by specimens that were collected during the 1940s to 1980s by Abrahamyan and Arakelyan, both from Armenia and Nakhichevan.

All ground specimens were selected among recently collected material as historical specimens cannot be sectioned; thus, the latter have been used only for measurements. The internal morphology of specimens was investigated by using the standard technique of serial sections and acetate peels. Almost complete articulated specimens were coated with magnesium oxide before being photographed with a Canon EOS 700D camera. Afterwards, all images were further processed using Adobe Photoshop CS6. Specimens selected for scanning electron microscopy were coated with gold and digitization of their micro-ornament was performed by the use of a ZEISS EVO Scanning Electron Microscope.

Systematic paleontology

The supraspecific classification follows [START_REF] Savage | Rhynchonellida[END_REF] and Savage (2007) for the Order Rhynchonellida instead of the one adopted by Sartenaer (2001Sartenaer ( , 2003) ) wherein the Subfamily Ripidiorhynchinae Savage, 1996 is elevated to the family level with Ripidiorhynchus Sartenaer, 1966 as its only representative, except otherwise stated, and the one suggested by Alvarez and Rong (2002) for the Order Athyridida.

Order Rhynchonellida [START_REF] Kuhn | Lehrbuch der Paläozoologie: Stuttgart[END_REF] Superfamily Rhynchotrematoidea Schuchert, 1913Family Trigonirhynchiidae Schmidt, 1965Subfamily Trigonirhynchiinae Schmidt, 1965 Genus Sartenaerus Özdikmen, 2008 Type species.-Camarotoechia baitalensis Reed, 1922.

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Remarks.-Camarotoechia baitalensis was selected by Sartenaer (1970) as the type species of his new genus Centrorhynchus. Although [START_REF] Savage | Rhynchonellida[END_REF] placed this genus in the subfamily Hemitoechiinae, Nicollin and Brice (2004: p. 440) noted that it should be reassigned to the subfamily Trigonyrhynchiinae because its septalium is posteriorly covered. Finally, as the name Centrorhynchus Luehe, 1911 was preoccupied for a genus of parasitic worms (Acanthocephala), Özdikmen (2008) introduced a new genus name Sartenaerus for Centrorhynchus sensu Sartenaer (1970). Mottequin et al. (2014) indicated that the genus Centrorhynchus (= Sartenaerus) first occurs in the middle Famennian, but the brachiopod record from Armenia establishes that it was already present in the lower part of this stage.

Sartenaerus baitalensis (Reed, 1922) Figures 3-4, 16-18; Table 1 1922 Camarotooechia baitalensis Reed, p. 94, pl. 14, figs. 11-21. 1922 Camarotooechia baitalensis comitata, var. nov.;Reed, p. 97, pl. 14, figs. 24-25;pl. 15, figs. 1-3a. 1922 Camarotooechia baitalensis transversalis, var. nov.;Reed, p. 97, pl. 14, figs. 22-23. 2019 Sartenaerus baitalensis; Serobyan et al. p. 9, 14 (see for a complete synonymy).

Occurrence and age.-This species was first described by Reed (1922) from the Famennian (the lowest and uppermost parts excluded; Sartenaer, 1970) of Pamir (Tajikistan). In Armenia it was first reported by Abrahamyan (1957) in the lower Famennian 'Cyrtospirifer' orbelianus Zone. This is consistent with the record of this species in Nakhichevan (Mirieva 2010).

F o r R e v i e w O n l y
Description.-Shell medium-sized, wider than long, strongly dorsibiconvex, rounded subpentagonal to transversally ovate in outline; widest more anteriorly to midlength; highest slightly posteriorly to the front (in adults); anterior margin slightly emarginate to straight;

anterior commissure highly zigzagged and strongly uniplicate.

Ventral valve inflated with convex flanks sloping steeply towards zigzagged lateral commissures; highest at anterior margin, then decreasing gently or maintained towards the posterior margin; umbo wide, inflated; beak large, prominent, suberect; foramen unobserved; palintropes low, concave; sulcus shallow to moderately deep, wide, inconspicuously originating at umbo, well-delimited by bounding ribs, flat to slightly round-bottomed at front; tongue high to very high, wide, with sharp borders, subtrapezoidal in outline, strongly bent dorsally.

Dorsal valve strongly inflated, strongly curved in posterior and lateral profile views with convex flanks sloping steeply towards lateral commissures; highest slightly posteriorly to the front then moderately to strongly decreasing towards the posterior margin; beak obtuse, covering the delthyrium; fold starting at umbo, moderately high, well-defined, becoming relatively higher anteriorly.

Ornamentation of coarse, strong, angular ribs with rounded apices arising from beaks; 3 ribs in sulcus with one median rib usually stronger and 4 ribs on fold with two opposed ribs usually stronger, 6-7 ribs per flank; ribs wider than interspaces.

Ventral valve interior (Fig. 4) with strong and relatively short dental plates, subparallel posteriorly then converging ventrally more anteriorly; teeth strong, crenulated; ventral muscle field flabellate anteriorly then becoming hastate or subtrapezoidal (Fig. 4(2.2-3)); lateral apical cavities strongly filled in by callosities. Dorsal valve interior with long and quite high septum,

F o r R e v i e w O n l y
extending up to 15% of the valve length; septalium narrow, relatively short, without cover; dental sockets large; hinge plates long, divided immediately anteriorly to septalium; crural bases horizontal.

Material examined.-Thirty-four articulated specimens, six ventral and four dorsal valves; 12 articulated specimens, two ventral and three dorsal valves come from the Ertych section; 11 articulated specimens, two ventral and two dorsal valves from the Djravank section and 11 articulated specimens, two ventral valves from the Noravank section.

Ontogeny.-Juveniles display all external morphological characters that are typical for this species with the exception of their maximum height, which is at about midlength of the shell, while the maximum height of adults is situated close to the front. Our collections contain juvenile specimens which may be split in to two groups based on their width/thickness ratio; some of them (Fig. 3. 1-5) are more inflated than their relatively older representatives. The shell growth follows a linear model, as this is more particularly reflected by the rather high coefficient of determination obtained for the ratios of length/width and width of sulcus/width (Fig. 5; see also the measurements provided in Table 1).

Remarks. -Sartenaer (1970) erected the genus Centrorhynchus (= Sartenaerus Özdikmen, 2008) based on the illustrations of Camarotoechia baitalensis in Reed's (1922) publication, as well as his own appreciation of a few specimens of this species coming from upper Famennian (?) strata of Pamir, which were offered to him by Rzhonsnitskaya in January 1964 during his stay in St.

Petersburg and they are stored now at the RBINS. It is pertinent to highlight here that the internal

F o r R e v i e w O n l y
structure of the type material of Sartenaerus baitalensis was poorly known as neither Reed (1922), nor Sartenaer (1970), had provided any drawings of serial sections. Our material is externally undistinguishable from Reed's species. This is also true for the internal features, with the single exception that none of our eight ground specimens displayed the connectivum that was reported by Sartenaer (1970) for this species. However, as noted by Brice (1967Brice ( , 1971) ) for S.

charakensis, this delicate structure is not always preserved. Only the serial sectioning of topotypic material of S. baitalensis will shed light on the real development of its connectivum.

Sartenaerus charakensis (Brice, 1967)

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Holotype.-An articulated specimen (AF 3GK 40) from the middle-upper Famennian of Ghor province, Afghanistan (Brice, 1967, pl. 8, fig. 3a-e).

Occurrence and age.-Although Brice (1967) considered initially that this species occurs in the upper Frasnian-lower Famennian strata of Afghanistan, she later specified (Brice 1971) that Sartenaerus charakensis is restricted in the lower to upper Famennian interval and that it appears to be rare above the Dmitria seminoi brachiopod Zone (see Fig. 2). Mirieva (2010) indicated the presence of S. charakensis in Nakhichevan within the 'Cyrtiopsis' orbelianus-'C.' armenicus and Dmitria seminoi brachiopod zones of Rzhonsnitskaya & Mamedov (2000). Afterwards, [START_REF] Grechishnikova | The Famennian-Lower Carboniferous Reference Section Geran-Kalasi (Nakhichevan Autonomous Region, Azerbaijan)[END_REF] reported the latter species in the younger deposits of Nakhichevan, more precisely in the Enchondrospirifer ghorensis-Cyrtospirifer pamiricus Zone.

This study establishes for the first time the presence of this species in older Famennian levels in the Lesser Caucasus, in the lower Famennian 'C.' orbelianus Zone of Abrahamyan (1957).

Description. Our material differs slightly from the S. charakensis from Afghanistan (Brice 1967(Brice , 1971) ) Occurrence and age.-The specimens were collected from the lower Famennian orbelianus Zone of Abrahamyan (1957) of the Noravank and Djravank sections (Fig. 1).

Description.-Shell small-sized (ca. Occurrence and age.-The specimens were collected from the lower Famennian orbelianus Zone of Abrahamyan (1957) of the Djravank section (Fig. 1).

Description Ventral valve interior (Fig. 9) with thin, long and subparallel dental plates; teeth strong; central apical cavity wide; lateral apical cavities poorly infilled by callosities.

Dorsal valve interior with relatively thick and low septum (Fig. 9(1.9-2.1)); septalium wide, relatively deep, covered anteriorly by stout connectivum bearing a median crest; dental sockets large.

Material examined.-Two partly exfoliated articulated specimens.

Remarks.-The external and internal features observed in the two studied specimens argue for its tentative assignment to genus Gesoriacorostrum Sartenaer, 2003, which presence in the SAB is recently documented by Pakhnevich in Alekseeva et al. (2018a). However, the fold and sulcus are perceptible only anteriorly on our specimens, while the original material from the Boulonnais region in France displays fold and sulcus that start from midlength; in addition, parietal ribs are absent on our specimens.

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Superfamily Rhynchoporoidea Muir-Wood, 1955Family Rhynchoporidae Muir-Wood, 1955 Subfamily Greirinae Erlanger, 1993 Genus Greira Erlanger, 1993 Type species.-Greira transcaucasica Erlanger, 1993.

Greira transcaucasica Erlanger, 1993 Figures 10-11, 16-18; Table 3 1993 Greira transcaucasica Erlanger, p. 120, text-figs. 1 and 2. 2002 Greira transcaucasica;Savage, p. 1233, fig. 840, 2a-o (copy of Erlanger 1993, fig.1, 2a-d; fig. 2).

2018a Greira transcaucasica; Pakhnevich in Alekseeva et al.,p. 855,916,pl. 8,fig. 4; text-fig.

58.

Holotype.-An articulated specimen (PIN 4127/1042) from the lower Famennian'Mesoplica' meisteri Zone of Grechishnikova et al. (1982), left bank of the Arpa River, between Geran-Kalasy and Kabakhal mountains, Nakhichevan (Erlanger, 1993: text-fig. 1a-d).

F o r R e v i e w O n l y
Occurrence and age.-This species is considered by Erlanger (1993) as one of the oldest punctate rhynchonellides which are particularly abundant and diverse with four species and subspecies [START_REF] Abrahamyan | Novyye vidy brakhiopod iz famenskikh otlozheniy Armyanskoy SSR[END_REF](Abrahamyan, , 1957;;Sartenaer and Plodowski (2003) known from the middleupper Famennian succession of the South-Armenian Block. Initially G. transcaucasica was described by Erlanger (1993) from the lower Famennian 'Mesoplica' meisteri Zone of Grechishnikova et al. (1982), equivalent to the 'Mesoplica' meisteri-Cyrtospirifer asiaticus Zone of Rzhonsnitskaya and Mamedov (2000) in Nakhichevan (Paknevich in Aleksseva et al.

(2018a)). This is the first time that this species is recorded within the Armenian sections, where it occurs in slightly younger strata, in the lower Famennian 'Cyrtospirifer' orbelianus Zone of Abrahamyan (1957).

Description.-Shell medium-sized, aequibiconvex to dorsibiconvex, wider than long, widest at about midlength, transversally elliptic in outline; anterior margin slightly emarginate to straight ;

anterior commissure uniplicate and serrate.

Ventral valve regularly convex in posterior and lateral profile views, with flanks sloping gently towards the lateral commissures; umbo small but prominent; beak small, inclined to straight; foramen unobserved; sulcus wide, shallow to moderately deep, inconspicuously originating from midlength or more anteriorly, flat-to round-bottomed at front; tongue variable in its height, low to moderately high, not perpendicular to the commissural plane, subtrapezoidal in outline.

Dorsal valve slightly inflated with flanks sloping gently to moderately towards the lateral commissures; fold wide, generally low, inconspicuously originating from midlength or more anteriorly, becoming more or less prominent at the anterior margin, flat-topped at the front. Ornamentation made of low, angular ribs, running from beak, becoming weaker towards the posterolateral margins; 9-13 ribs on each flank, 4-5 ribs in sulcus, 4-6 ribs on fold; 5-6 ribs per 5 mm at the anterior margin near the sulcus and fold; ribs in sulcus and on fold somewhat wider than those present on the flanks; ribs wider than interspaces.

Ventral valve interior (Fig. 11) with thin, long, short and divergent dental plates; lateral apical cavities poorly infilled by callus; teeth small, rounded in transverse section.

Dorsal valve interior (Fig. 11) with wide and Y-shaped septalium, covered anteriorly; sockets smooth; dorsal median septum low but long, extending one-quarter of valve's length, crural bases proximally triangle-shaped in section, dorsally convergent.

Material examined.-Twenty-six articulated specimens and two ventral valves; 14 articulated specimens and two ventral valves come from the Ertych section and 12 articulated specimens from the Noravank section.

Ontogeny.-The shell growth of Greira transcaucasica Erlanger follows a linear model, as this is reflected by the high coefficient of determination obtained for the ratios of length/width, thickness/width and width of sulcus/width (Fig. 13; see also the measurements provided in Table 2).

Remarks.-Our material slightly differs from the holotype of Greira transcaucasica; according to Erlanger (1993) the interspaces of this species are wider than ribs, but the specimens from Armenia display ribs that are wider than the interspaces. This is consistent with the description of Occurrence and age.-The specimens were collected from the lower Famennian orbelianus Zone of Abrahamyan (1957) of the Ertych section (Fig. 1).

Description.-Shell small-sized (12.7 Pakhnevich observed irregularly spaced punctae along the whole shell, whereas in our material puncta-like structures are displayed only near the umbo (Fig. 14.6-8), and it is highly questionable whether that is one of the typical morphological characteristics of our material or whether they are just the results of dissolution due to the action of meteoric waters.

Order Athyridida Boucot, Johnson, andStaton, 1964 Suborder Athyrididina Boucot, Johnson, andStaton, 1964 Superfamily Athyridoidea Davidson, 1881 Family Athyrididae Davidson, 1881 Subfamily Cleiothyridininae Alvarez, Rong, and Boucot, 1998 Genus Crinisarina Cooper and Dutro, 1982 Type species.-Crinisarina stainbrooki [START_REF] Mottequin | Late middle Frasnian to early Famennian (Late Devonian) strophomenid, orthotetid and athyridid brachiopods from southern Belgium[END_REF](pro Cleiothyridina reticulata Stainbrook, 1947).

Crinisarina pseudoglobularis new species  Abrahamyan (1957) it is restricted to the lower Famennian 'Cyrtospirifer' orbelianus Zone of Abrahamyan (1957) and according to Rzhonsnitskaya and Mamedov (2000) in the 'Cyrtiopsis' orbelianus-'Cyrtiopsis' armenicus Zone of Nakhichevan.

Description.-Shell medium-sized, relatively equidimensional, rounded subpentagonal in outline, aequibiconvex, widest at about midlength or slightly posteriorly; highest in the posterior third of the valve; anterior margin straight to poorly emarginate; anterior commissure uniplicate.

Ventral valve inflated with flanks sloping moderately to strongly towards the lateral commissures; highest in the posterior third of the valve, then decreasing progressively towards the anterior margin; umbo strongly inflated, prominent; beak suberect to erect, pierced by a permesothyrid foramen; sulcus poorly defined posteriorly, more defined anteriorly, wide at the front, very shallow, flat-to round-bottomed at the front, subtrapezoidal to semioval in outline, perpendicular to the commissural plane with distal part sometimes bent dorsally.

Dorsal valve with upper surface dome-shaped (median part sometimes raised by the fold), regularly and strongly curved in posterior and lateral profile views with flanks sloping moderately towards the lateral commissures; highest in the anterior third of the valve (near umbo in juveniles) then progressively decreasing towards the anterior margin; umbo prominent; fold low, inconspicuously originating close to umbo, wide at the front, poorly defined, round-topped at the front.

Micro-ornament of imbricate, densely crowded growth lines projecting anteriorly and anterolaterally as flattened, radially-aligned solid spines (Fig. 14.16-18). Growth lines less Ventral valve interior (Fig. 15) with thin, relatively long and arched dental plates, supporting cyrtomatodont teeth that are subrectangular in transverse section (Fig. 17); thick lens of prismatic calcite is developed in the middle part of the valve below the well-developed umbonal cavity; lateral apical cavities moderately filled in by callosities.

Dorsal valve interior (Fig. 15) with conjunct, weakly concave ventrally to nearly flat inner hinge plates; outer hinge plates flat; myophragm low but long; spiral cones with at least 11 whorls laterally oriented.

Etymology.-In reference to the confusion made with the athyridide species Composita globularis (Phillips, 1836).

Additional material.-Fourty-three articulated specimens and five ventral valves; 15 articulated specimens and three ventral valves come from the Ertych section, 16 articulated specimens and two ventral valves from the Djravank section and 12 articulated specimens from the Noravank section.

Ontogeny particularly reflected by the rather high coefficient of determination obtained for the ratios of length/width and width of sulcus/width (Fig. 18; see also the measurements provided in Table 3).

Remarks.-Reported initially by Arakelyan (1952) as Athyris globularis, this species was found both in Armenia and Nakhichevan, but it was never described and illustrated. It was considered by Abrahamyan et al. (1973) and Arakelian (1975) The new species may be distinguished from C. reticulata (Gosselet, 1877) as revised by [START_REF] Mottequin | Late middle Frasnian to early Famennian (Late Devonian) strophomenid, orthotetid and athyridid brachiopods from southern Belgium[END_REF], by its more inflated and less transverse shell, less developed sulcus and fold and subtrapezoidal to semioval tongue.

Comparative quantitative analyses

The size distributions between four studied species have been compared and tested. Statistical analysis, i.e., ANCOVA (test for comparison of several models of simple linear regression) were performed in order to determine if the regression line slopes of our four samples are significantly different. Statistical analysis were performed under the free PAST software.

The scatter plot of Width/Length ratios and linear regression lines for all the four taxa are presented Figure 16. The shell growth for each species follows a linear model, as this is more particularly reflected by the significant coefficient of correlation (Fig. 16

Discussion

Although a precise paleolatitudinal evaluation of the Late Devonian position of the SAB is still hampered due to the remagnetization of Upper Paleozoic rocks following the Late Cretaceous obduction of ophiolites (Meijers et al. 2015), existing paleogeographic reconstructions place the SAB at the junction between the Iranian terranes (to the east) and the Anatolide-Tauride microplate (to the west). It was thus an integral part of the northern passive margin of Gondwana, facing the Paleotethys ocean to the north (Fig. 19). Thus, during the Late Devonian it was part of a huge platform that was positioned at the southern hemisphere tropical carbonate development zone (Brock and Yazdi 2000). The taxonomic assessment of brachiopods collected from the lower Famennian 'Cyrtospirifer' orbelianus Zone of Abrahamyan (1957) cautious should be exercised on questions of taxonomic consistency, comparison of assemblages of similar age and biofacies (Brock and Yazdi 2000). In that respect the two species of the Famennian genus Sartenaerus found in the orbelianus Zone of Armenia (S. baitalensis and S. charakensis) are of particular paleobiogeographic significance as they point to a likely wide lower Famennian brachiopod bioprovince developed along the northern Gondwana margin, from the SAB to Afghanistan and Pamir (Fig. 19). However, it should be stressed that in spite of the well constrained age of the occurrence of S. baitalensis in the Lesser Caucasus (the species occurs only in the orbelianus Zone) this is not the case for the occurrence of S. baitalensis in Pamir (Reed 1922). Finally, the apparent absence of both species in other parts of the northern Gondwanan margin, especially in Morocco may be due to the presence of deeper (cephalopodbearing) facies for this interval and therefore it may reflect a paleoenvironmental rather than paleobiogeographical signal. This is the first time that the genus Porthmorhynchus is recognized (although doubtfully) from the Armenian sections. It is also worth stressing that the genus is known so far only from the Frasnian, as its type species P. ferquensis is known from the middleupper Frasnian of the Boulonnais region and Nakhichevan (Pakhnevich in Alekseeva et al.

(

Conclusions

Taxonomic reassessment of the rhynchonellide brachiopods collected from the lower Famennian 'Cyrtospirifer' orbelianus brachiopod Zone of Abrahamyan (1957) from three distinct localities of central Armenia confirm the presence of a number of species known previously (e.g.

Sartenaerus baitalensis, S. charakensis and Greira transcaucasica). However, this is the first time that extensive documentation of the internal structure of Sartenaerus baitalensis is provided and this is of particular significance as it is the type species of a biostratigraphically important genus. Thus, the brachiopod record from Armenia establishes firmly the presence of the Famennian genus Sartenaerus since the lower Famennian and not since the middle Famennian as it was previously believed (Mottequin et al. 2014). It is also the first documentation of S. charakensis in the Armenian sections; moreover, its stratigraphic range is extended here down to the orbelianus Zone (it was previously known from the ghorensis-pamiricus Zone). The intraspecific variability of Greira transcaucasica is documented and its stratigraphic range revised to include its presence up to the orbelianus Zone. This is also the occasion to introduce a by Abrahamyan (1957) in central Armenia and by Grechishnikova et al. (1982) and Rzhonsnitskaya and Mamedov (2000) in Nakhichevan. It also includes the regional conodont zonation established by Aristov (1994) in Nakhichevan and the standard conodont zones of [START_REF] Ziegler | The Late Devonian standard conodont zonation[END_REF].

Figure 3. Sartenaerus baitalensis (Reed, 1922) Sartenaerus baitalensis (Reed, 1922), Sartenaerus charakensis (Brice, 1967) Sartenaerus baitalensis (Reed, 1922), Sartenaerus charakensis (Brice, 1967) Table 1. Measurements in mm and ratios of Sartenaerus baitalensis (Reed, 1922).

Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

Table 2. Measurements in mm and ratios of Sartenaerus charakensis (Brice, 1967).

Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

Table 3. Measurements in mm and ratios of Greira transcaucasica Erlanger, 1993 Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

Mots clés

Brachiopodes; Spiriferida; Famennien inférieur; Gondwana; Arménie.

Introduction

The Upper Devonian sedimentary sequences of Armenia are highly fossiliferous and contain a diverse and well-preserved brachiopod fauna (Abrahamyan, 1957(Abrahamyan, , 1964(Abrahamyan, , 1974;;Arakelyan, 1964), which remain largely undocumented from a taxonomic and biostratigraphic point of view. Re-investigation of this fauna is crucial to better understand Late Devonian changes in brachiopod diversity and palaeobiogeographic distribution. In Armenia, Devonian outcrops were first examined by the famous German geologist Hermann Abich, considered as the 'Father of Caucasian Geology' [START_REF] Milanovsky | Hermann Abich (1806-1886): the "Father of Caucasian Geology" and his travels in the Caucasus and Armenian Highlands[END_REF]. Abich (1858) described a number of new brachiopod species from the Lesser Caucasus, notably the spiriferide species Spirifer orbelianus. The latter was erroneously reported afterwards in the Franco-Belgian Basin by Gosselet (1874), and later in different parts of the world (see Sartenaer, 1974 for an up-to-date review, and references below).

Due to its great potential for biostratigraphic correlations of lower Famennian successions throughout the Lesser Caucasus, re-investigation of S. orbelianus is a necessary task as its affinities at the genus level still remain unclear, in spite of the extensive taxonomic studies led by Abrahamyan (1957Abrahamyan ( , 1974) ) and Afanasjeva (in Alekseeva et al., 2018a). The purpose of the present study is to reassess the taxonomy of S. orbelianus Abich, 1858 on the basis of recently collected material from the lower Famennian of Central Armenia, with implications for its palaeobiogeographic distribution.

Stratigraphic and palaeogeographic settings

In the southern part of Central Armenia crops out a ca. 1,500 m-thick Middle Devonian-Lower Carboniferous sequence of platform carbonate deposits (Fig. 1). They record the earliest depositional history of Palaeozoic sediments in the area; they were accumulated on a Gondwanan passive margin that was facing the Palaeotethys, situated to the north; this part of Gondwana was later individualized as the South-Armenian Block, following its northward migration and opening of Neotethys further to the South (Sosson et al., 2010). The Middle Devonian-Lower Carboniferous sequences of Armenia constitute a continuous succession of mixed carbonatesiliciclastic deposits, developed in a shallow water environment. The Upper Devonian-Lower Carboniferous sequences were subdivided by Abrahamyan (1964) and Arakelyan (1964) into twelve 'formations'. However, in practice, most of them have very similar lithological characteristics and they cannot be recognized in the field without knowledge of their brachiopod assemblages. Thus, they have a biostratigraphic rather than lithostratigraphic significance (see Serobyan et al., 2019). It is worth noting that [START_REF] Abrahamyan | Granitsa Devona i Nizhnego Karbona (The Devonian and Lower Carboniferous boundary)[END_REF] described these stratigraphic units as 'horizons' and no longer used the term 'formation'. In Armenia, Famennian deposits are more widespread than the Frasnian ones. The latter consist mainly of marly and sandy limestones, biogenic limestones rich in brachiopods and corals (a few gastropods and cephalopods were also found) with interbedded sandstones and quartzites, whereas the Famennian is chiefly represented by biogenic and sandy limestones, quartzites and shales. The first Devonian biostratigraphical zonal scheme based on brachiopods was established by [START_REF] Rzhonsnitskaya | Devonskiye otlozheniya Zakavkaz[END_REF].

Afterwards, in her groundbreaking monograph, Abrahamyan (1957) discussed the occurrence and stratigraphic distribution of the brachiopod species she dealt with; she thus proposed a new continuous biostratigraphic scheme characterized by marker species or species assemblages (Fig. 2). This was a major step forward, as the existing Devonian brachiopod biostratigraphic scheme available at the time for the region was very rudimentary. As the Upper Palaeozoic sedimentary sequences of Armenia continue into Nakhichevan, the stratigraphic and faunal similarities in terms of brachiopods allowed Mamedov and Rzhonsnitskaya (1985) to use and refine Abrahamyan's zonal scheme for the entire region of the Lesser Caucasus (or Transcaucasia). Subsequently, their zonal scheme was updated by Rzhonsnitskaya and Mamedov (2000) and correlated with the international conodont biozonation based on the conodont study of Aristov (1994) carried out in Nakhichevan.

Material and methods

The examined material was collected from the Noravank, Ertych and Djravank sections (Fig. 1) during several field seasons organized in 2018 and 2019. It comes from marly limestones and shales of the lower Famennian Ertych horizon (Fig. 2), which can be correlated with the 'Cyrtospirifer' orbelianus Zone of Abrahamyan (1957) and the 'Cyrtiopsis' orbelianus-Cyrtiopsis armenicus Zone of Rzhonsnitskaya and Mamedov (2000). In total 80 articulated brachiopod shells and 15 dissociated valves were collected, the main part of which is derived from a soft, weathered surface that provided well-preserved, nearly sediment-free specimens. The bulk of the specimens illustrated and investigated herein is housed at the Geological Museum of the Institute of Geological Sciences of the National Academy of Sciences of Armenia, Yerevan (IGSNASRAGM). Some specimens are deposited at the Royal Belgian Institute of natural Sciences, Brussels (RBINS) and others at the University of Lille (USTL). The recently collected material was compared with Abrahamyan's specimens, collected in Armenia during the 1940s to 1980s, most of which are now stored at the IGSNASRAGM. The internal structure of the newly collected articulated specimens identified as A. orbelianus (Abich, 1858) found in the three sections (Fig. 1) was investigated by using the standard technique of serial sections and acetate peels. The latter were assembled between microscope slides and photographed under a binocular microscope Olympus SZX 12. Afterwards, the photographs were transferred to CorelDRAW X7 software and internal details were drawn using a digital drawing tablet. Furthermore, in order to capture the fine details of the internal structure, the ground specimens were photographed directly under a Canon EOS 700D camera that was attached on a Zeiss SteREO Discovery V20

Microscope. Intact brachiopod specimens were coated with magnesium oxide or ammonium chloride sublimate before being photographed. All images have been further processed using Adobe Photoshop CS6. Additionally, the IGSNASRAGM 3895/PS 3001 specimen was coated with gold and the digitization of the micro-ornament of the latter was performed by ZEISS EVO Scanning Electron Microscope. RBINS specimens selected for scanning electron microscopy were observed using a low vacuum SEM, an ESEM FEI Quanta 200, but not coated with gold.

Systematic palaeontology

The supraspecific classification adopted herein follows [START_REF] Carter | Spiriferida[END_REF] for the Order Spiriferida. The synonymy list only concerns the report of the species in the South-Armenian Block.

Order Spiriferida Waagen, 1883Suborder Spiriferidina Waagen, 1883 Superfamily Cyrtospiriferoidea Termier and Termier, 1949 Family Cyrtospiriferidae Termier and Termier, 1949 Subfamily Cyrtospiriferinae Termier and Termier, 1949 Genus Aramazdospirifer gen. nov. Nalivkin's species and does not belong to Aramazdospirifer gen. nov. (see [START_REF] Paeckelmann | Beiträge zur Kenntnis devonischer Spiriferen[END_REF][START_REF] Vandercammen | Essai d'étude statistique des Cyrtospirifer du Frasnien de la Belgique[END_REF]. It is also probable that Cyrtospirifer (Cyrtospirifer) pentagonalis Sidjachenko (1962) described from the Famennian of Central Kara-Tau should be assigned to Aramazdospirifer gen. nov. as it shares many common features with the new genus. More precisely its inflated and subpentagonal shell that is ornamented with closely spaced and flattened ribs, acute to mucronate cardinal extremities and apsacline triangular ventral interarea that fit well with the diagnosis of the new genus. Nevertheless, the micro-ornament, the internal morphology and the type of pseudodeltidium of the latter species is unknown. Finally, Cyrtospirifer aquilinus Romanowski sensu Nalivkin (1930) described from the Central Kara-Tau and along the headwaters of the Naryn river (Kazakhstan) might also be assigned to the new genus, although it lacks median and longitudinal elevations in sulcus and on fold. However, its micro-ornament and internal morphology is unknown. All these uncertainties preclude the possibility of a definite assignment to Aramadzospirifer.

Etymology: In honor of Aramazd, who was the chief god in pre-Christian Armenian mythology.

Diagnosis: Shell of medium-size, ventribiconvex, subpentagonal, wider than long to longer than wide, with mucronate cardinal extremities; generally widest at hinge line; ventral interarea moderately high, apsacline; delthyrium wide and most of its height covered by a pseudodeltidium, the latter is composed of several distinct plates, with submesothyrid foramen; fold and sulcus moderately wide, well-defined, median longitudinal elevation developed in sulcus and frequently on fold; ribs numerous, usually simple on flanks, increasing by bifurcation in sulcus and on fold;

micro-ornament capillate both on ribs and in interspaces; dental plates long, strong and intrasinal; delthyrial plate well-developed; unsupported ctenophoridium with numerous vertical lamellae; crural plates short; dorsal myophragm present.

Remarks: Aramazdospirifer gen. nov. is included in the Superfamily Cyrtospiriferoidea based on the presence of dental plates, a ctenophoridium, a well-developed delthyrial plate, and capillate ornamentation. Although a thorough revision of this superfamily, recommended by Ma and Day (2000), is still pending, Aramazdospirifer gen. nov. is assigned to the Family Cyrtospiriferidae, as defined by Johnson (2006), due to the development of ribs in the sulcus and on fold. Additionally, its wide hinge line argues for its assignment to the Subfamily Cyrtospiriferinae rather than to the Cyrtiopsinae. Afanasjeva in Alekseeva et al. (2018a) examined some specimens collected from the Armenian sections and reassigned Abich's species to the late Givetian?early Frasnian genus Uchtospirifer Liashenko, 1957 known from South Timan (Russia). Aramazdospirifer gen. nov. shares indeed several external and internal characters with Uchtospirifer Ljaschenko, 1957 sensu Sokiran (2006). More particularly, both genera display a subpentagonal shell that is ornamented with closely spaced and flattened ribs (also in sulcus and on fold), an apsacline and triangular ventral interarea, divergent dental plates, and an unsupported ctenophoridium. However, Aramazdospirifer gen. nov. differs from Uchtospirifer by its much more inflated shell, acute to mucronate cardinal extremities, wider hinge line, clearly defined longitudinal and median elevation in sulcus and similar elevation often developed on fold, and the type of pseudodeltidium formed by several distinct plates. Furthermore, it is worth noting that Aramazdospirifer gen. nov. has narrower ribs perceptible along the whole length of its sulcus and fold, whereas the median ribs of Uchtospirifer are variably developed, sometimes flattened to imperceptible or absent. Moreover, the micro-ornament of the new genus lacks the tubercles observed on Uchtospirifer.

Externally Aramazdospirifer gen. nov. resembles also to the Famennian genus Wenjukovispirifer Oleneva, 2016 mainly in terms of its rounded subpentagonal outline, ventribiconvex lateral profile, acute to mucronate cardinal extremities, wide hinge line, welldefined and triangular ventral interarea, wide sulcus and fold bearing bifurcating ribs that are narrower than those present on the flanks. However, Aramazdospirifer gen. nov. differs by its median and longitudinal elevation in sulcus and similar elevation frequently displayed on fold, and its pseudodeltidium that is formed by several distinct plates with minute submesothyrid foramen.

Additionally, Aramazdospirifer gen. nov. lacks pustules that are observed in Wenjukovispirifer. It is difficult to compare the internal morphology of these genera as Oleneva (2016) did not illustrate any serial sections. Nevertheless, she mentioned the presence of a median septum situated in the ventral interior of Wenjukovispirifer, a character that is not observed in Aramazdospirifer gen. nov.

The new genus differs strongly from Cyrtospirifer Nalivkin in Frederiks, 1924, by its more globular, longitudinally elongated and inflated shell, well-developed pseudodeltidium, longitudinal and median elevation in sulcus and similar elevation often developed on fold and the type of micro-ornament. Internally, these genera appear to be similar, though Aramazdospirifer gen. nov. possesses an unsupported ctenophoridium, while the latter is supported by an apical Description.-Shell medium-sized (up to 39 mm in width and 39.1 mm in length), wider than long to longer than wide, generally ventribiconvex, rounded subpentagonal in outline, widest at hinge line, highest at about midlength; cardinal extremities acute to mucronate, but strongly extended in some specimens; anterior margin strongly excavated by sulcus, emarginate; anterior commissure uniplicate.

Ventral valve strongly inflated, rounded pentagonal in outline, with convex flanks sloping steeply towards lateral commissures; highest at about midlength or slightly posteriorly; umbo strongly inflated, large and prominent; beak erect (85-90°), interarea apsacline, triangular, moderately high, well-defined, concave; delthyrium wide, with most of its height covered by pseudodeltidium, the latter formed by several distinct plates; foramen minute, rounded to ovate;

Discussion

Aramazdospirifer orbelianus was named by Abich (1858) 440, und zwar in sehr grossen Mengenverhältnissen gefunden worden', i.e., the author found this species in large numbers only in the h (impure limestones) and k (limestones with glauconitic sand) horizons of the profile exposed on the slopes of the valley of the Gnishik river (Fig. 1). These are apparently the marly/sandy limestone layers constituting the lower Famennian sequence exposed below the Noravank monastery, which is one of the most notable monasteries built by the Orbelian dynasty. Abich's species was later reported by Gosselet (e.g. 1874Gosselet (e.g. , 1880Gosselet (e.g. , 1894) ) in northern France and southern Belgium, from sequences accumulated close to the Givetian-Frasnian boundary. However, according to Sartenaer (1974) and [START_REF] Mottequin | An annotated catalogue of types of Silurian-Devonian brachiopod species from southern Belgium and northern France in the Royal Belgian Institute of Natural Sciences (1870-1945), with notes on those curated in other Belgian and foreign institutions[END_REF], the Franco-Belgian material was erroneously identified as Spirifer orbelianus and needs further investigation. Reed (1922) reported a single specimen from Pamir, identified as S. orbelianus and stated that the species displays all the superficial features typical for Abich's species. Nonetheless, his single illustrated specimen has rounded cardinal extremities, coarser ribs with very narrow interspaces and fewer ribs in sulcus and on fold; it also lacks a median longitudinal elevation. We thus consider this specimen as distinct from Abich's species and in need of re-examination. Bonnet (1947, p. 32, p. 39) noted the presence of Spirifer orbelianus in Frasnian strata of Armenia, but this occurrence remains highly questionable as he did not illustrate his material (Sartenaer, 1974). Gatinaud (1949) erected the genus Lamarckispirifer and assigned many species to it, including Abich's species, but as noted by Ma and Day (2007), the latter species differs externally by its inflated shell and cannot be attributed to that genus. During the 'golden era' of Palaeozoic studies in Armenia (1950s to 70s) A. orbelianus was reported extensively by Abrahamyan (1957Abrahamyan ( , 1974)), Abrahamyan et al. (1973) and Arakelyan (1952Arakelyan ( , 1964)). Abrahamyan (1957) assumed that A. orbelianus could be a sister species of 'Cyrtiopsis' armenicus as the latter appeared in aslightly younger horizon. Therefore, Abrahamyan (1974) incorrectly assigned both species to the lower Famennian genus Cyrtiopsis [START_REF] Grabau | Stratigraphy of China. Part 1. Palaeozoic and older: Geological Survey of China[END_REF]. Sartenaer (1974) discussed several reports of A. orbelianus from Africa, the Franco-Belgian basin and Iran. He rightly concluded that none of them corresponds to Abich's species. In sum, A.

orbelianus is known only from the South-Armenian Block (Central Armenia and possibly Nakhichevan).

Conclusions

The taxonomic revision of Spirifer orbelianus Abich, 1858, based on material collected from its type locality in Central Armenia and complemented by the specimens described by Abrahamyan (1957), led us to define the new cyrtospiriferine genus Aramazdospirifer. A. orbelianus (Abich, 1858) is one of the most useful species for the biostratigraphy of the lower Famennian in the Lesser Caucasus due to its short stratigraphic range and abundance. In addition to its type species, which appears to be endemic in the South-Armenian Block, several other Famennian species described from Central Kazakhstan and the East European Platform may be also considered for assignment to the genus Aramazdospirifer, although they are in need of a modern taxonomic reassessment.

Further studies on Armenian material are still needed in order to complement the recent revisions of the Famennian brachiopod faunas from the area of northern Gondwana that now corresponds to the Lesser Caucasus, Afghanistan and Iran (Alekseeva et al., 2018a, b;Mottequin and Brice, 2019). Aramazdospirifer orbelianus (Abich, 1858). (Abich, 1858) Abréviations: W-largeur de la coquille, L-longueur de la coquille, T-épaisseur de la coquille, Ws-largeur du sulcus, dL-longueur de la valve dorsale.

Table 1. Measurements and ratios in mm of Aramazdospirifer orbelianus (Abich, 1858) Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

Tableau 1. Mesures et rapports en mm de Aramazdospirifer orbelianus (Abich, 1858) Abréviations: W-largeur de la coquille, L-longueur de la coquille, T-épaisseur de la coquille, Ws-largeur du sulcus, dL-longueur de la valve dorsale.

Résumé

  Les séries sédimentaires carbonatées-terrigènes et les brachiopodes du Dévonien supérieur d'Arménie centrale ont été ici étudiées à partir de trois coupes distinctes (Ertych, Djravank et Noravank). Leur interprétation paléoenvironnementale a été réalisée à partir des bio-et lithofaciès afin de reconstituer leurs milieu de dépôt. De plus, les coupes étudiées ont été corrélées lithostratigraphiquement, ainsi que biostratigraphiquement, en se basant sur leurs assemblages à brachiopodes. Vingt-six espèces de brachiopodes sont décrites sur la base d'un matériel récemment collecté. Quatre nouveaux genres de brachiopodes (Aramazdospirifer, Angustisulcispirifer, Pentagonospirifer et Tornatospirifer), ainsi que cinq nouvelles espèces (Ripidiorhynchus djravankensis, Cyrtospirifer pseudoasiaticus, Pseudocyrtiopsis areniensis, Pentagonaspirifer abrahamyanae et Angustisulcispirifer arakelyani) sont introduits. Toutes les espèces de brachiopodes sont examinées selon des concepts taxonomiques modernes; leurs caractéristiques internes et externes sont illustrées, à l'exception de quelques rares espèces. La variabilité morphologique intraspécifique des espèces décrites est documentée quantitativement. Le schéma biostratigraphique proposé auparavant pour l'intervalle Frasnien-Famennien du Petit Caucase (Arménie et Nakhichevan) est révisé. Plus particulièrement, la zone à Ripidiorhynchus gnishikensis-Angustisulcispirifer arakelyani, d'âge Frasnien, est proposée pour la faune trouvée dans les calcaires à péloïdes accumulés dans un cortège à haut niveau marin, alors que la zone à Aramazdospirifer orbelianus-Tornatospirifer armenicus, d'âge Famennien inférieur, est caractérisée par des packstones/grainstones de l'intervalle 4, déposés lors d'un événement transgressif. La présente étude documente également la diversité des brachiopodes signalée dans le Petit Caucase à travers l'intervalle Frasnien-Famennien inférieur et souligne un renouvellement majeur de faune parmi les rhynchonellides, les atrypides et les spiriférides. D'un point de vue paléobiogéographique, la faune étudiée a clairement des affinités avec celles connues dans d'autres régions de la marge nord-Gondwanienne, notamment celles qui s'étendent vers l'est du SAB (Bloc Ամփոփում Սույն աշխատանքում ուսումնասիրված են կենտրոնական Հայաստանի երեք կտրվածքների (էրտիչ, Ջրավանք և Նորավանք) վերին դևոնի կարբոնատ-սիլիկատային (կրաքարեր, ավազաքարեր և քվարցիտներ) նստվածքային հաջորդականություններն ու բրախիոպոդները։ Նստվածքային հաջորդականություների նստվածքակուտակման պայմանների վերականգնումը իրականացվել է կենսա-և լիթոֆացիաների ուսումնասիրությունների հիման վրա: Ավելին, ուսումնասիրված կտրվածքները կորելացվել են, ինչպես լիթոշերտագրական, այնպես էլ կենսաշերտագրական տեսանկյունից՝ բրախիոպոդային համալիրների վրա հիմնվելով: Աշխատանքում նույնականացվել և նկարագրվել է բրախիոպոդների քսանվեց տեսակ, որոնք գտնվել են Ֆրան-Ֆամենի (F-F) հաջորդական նստվածքներից: Բրախիոպոդների մանրակրկիտ ուսումնասիրության արդյունքում առաջարկվել է չորս նոր սեռ (Aramazdospirifer, Angustisulcispirifer, Pentagonospirifer և Tornatospirifer) և հինգ նոր տեսակ (Ripidiorhynchus djravankensis, Cyrtospirifer pseudoasiaticus, Pseudocyrtiopsis areniensis, Pentagonaspirifer abrahamyanae և Angustisulcispirifer arakelyani): Բրախիոպոդների բոլոր տեսակները հետազոտվել են ժամանակակից տաքսոնոմիական դասակարգումների համաձայն. աշխատանքում ներկայացված է վերջիններիս ինչպես արտաքին, այնպես էլ ներքին կառուցվածքը, բացի մի շարք հազվագյուտ տեսակների, որոնք ուսումնասիրված են միայն արտաքնապես: Ուսումնասիրված ուսոտանիների ներտեսակային մորֆոլոգիական փոփոխականությունը փաստագրված է քանակապես առաջին անգամ: Վերանայվել է Փոքր Կովկասի (Հայաստան և Նախիջևան) ֆրան-ֆամեն միջակայքի բրախիոպոդների նախկինում առաջարկված կենսաշերատագրական սխեման: Մասնավորապես, առաջարկվել է օգտագործել երկու նոր բրախիոպոդային զոնա՝ Ripidiorhynchus gnishikensis-Angustisulcispirifer arakelyani և Aramazdospirifer orbelianus-Tornatospirifer armenicus: Ripidiorhynchus gnishikensis-Angustisulcispirifer arakelyani զոնան բնորոշում է ծովի բարձր մակարդակի ժամանակ կուտակված ֆրանի հասակի նստվածքային առաջացումները` կազմված ավազային կրաքարերից և բնորոշում է ինտերվալ 1-ը: Aramazdospirifer orbelianus-Tornatospirifer armenicus զոնան բնորոշում է ստորին ֆամենի հասակի Ինտերվալ 4-ը, որի նստվածքակուտակումը տեղի է ունեցել տրանսգրեսիայի ընթացքում: Սույն աշխատանքում ուսումնասիրվել են նաև Փոքր Կովկասի ֆրան-ստորին ֆամենի հաջորդական նստվածքներից հայտնաբերված բրախիոպոդների կենսաբազմազանության փոփոխությունները: Նախկին աշխատանքների և ներկա տվյալների վերանայումը ցույց է տալիս, որ ֆրան-ֆամեն միջակայքում rhynchonellide, atrypide և spiriferide խմբերի բրախիոպոդների կենսաբազմազանության մեջ տեղի են ունեցել զգալի փոփոխություններ: Հնակենսաշխարհագրական տեսանկյունից, ուսումնասիրված ֆաունան հստակորեն կապված է Գոնդվանայի հյուսիսային հատվածի այլ տեղամասերում հայտնաբերված հասակակից բրախիոպոդային համալիրների հետ, հատկապես Հարավ Հայկական Բլոկից դեպի արևելք՝ մինչև Աֆղանստան և Պամիր ընկած տարածքները: Թեև հարկ է նշել, որ Հարավ Հայկական Բլոկում հայտնաբերվել են նաև բրախիոպոդի էնդեմիկ տեսակներ: Աշխատանքում քննարկվում է նոր առաջարկված չորս ցեղերի հնակենսաշխարհագրական տարածման առանձնահատկությունները՝ հաշվի առնելով այն հանգամանքը, որ նախկին աշխատություններում՝ Նախիջևանից, Պամիրից (Տաջիկստան), Կենտրոնական Ղազախստանից և Արևելյան Եվրոպայի պլատֆորմից բերված ֆամենի մի շարք տեսակներ սույն աշխատությունում վերագրվեցին նոր առաջարկված ցեղերին: Հանգուցային բառեր. Brachiopoda; Rhynchonellida; Atrypida; Athyrida; Spiriferida; Ֆրան; Ֆամեն; Կելվասարի կենսաբազմազանության ճգնաժամ; Գոնդվանա; Փոքր Կովկաս; Հարավ Հայկական Բլոկ; Հայաստան; Նախիջևան:

Figure 1 .

 1 Figure 1. Schematic geological map and distribution of the Upper Paleozoic sequences in the Lesser Caucasus (Central Armenia and Nakhichevan), including the location of the three sections mentioned in the present study (modified after Serobyan et al., 2019a).

Figure 2 .

 2 Figure 2. Late Devonian paleogeographic reconstruction of the Paleotethys ocean and its surrounding continents, including the position of the South Armenian Block along the northern margin of the Gondwana megacontinent (redrawn and modified after Denayer and Hoşgör, 2014, based on the maps of Stampfli et al., 2002).

Figure 3 .

 3 Figure 3. Biochronostratigraphic framework of the Frasnian-lower Famennian sedimentary sequences in the Lesser

  Repositories and institutional abbreviations.-Most of the illustrated material is housed at the Geological Museum of the Institute of Geological Sciences of the National Academy of Sciences of Armenia, Yerevan (IGSNASRAGM/PS), unless otherwise stated. The prefix PS indicates the Laboratory of Paleontology and Stratigraphy. The prefix IGSNASRAGM/AB points to the specimens belonging to Abrahamyan's collection. Part of the studied material is housed at the public paleontological collection of the University of Lille (USTL), France. The prefix RBINS is used for some specimens deposited at the Royal Belgian Institute of Natural Sciences, Brussels.

Figure 4 .

 4 Figure 4. (1) Southeastern view of the Ertych section. (2) The base of the section (Interval 1) displays nodular limestones, rich in brachiopods. (3) Calcareous sandstone (quartz-wacke) layer situated at the lower part of Interval 2 (Er1/5) and intercalated in black shale layers of which the lower one is ca. 8 m thick. (4) Intercalation of sandstones and black shales constituting the middle part of Interval 2. (5) Organic rich black shales of the upper part of Interval 2.

Figure 5 .

 5 Figure 5. Field views of the Ertych section. (1) Quartzite quarry explored at the Interval 3. (2) Close-up of quartzites cropping out in the quarry. (3) Black shale layers observed between the two quartzite beds and containing macro-plant remains. (4) Bioturbated sandstone (quartz-wacke) at the upper part of Interval 3. (5). Base of Interval 4 comprising oncolitic (Er19/92) and peloidal (Er19/95) grainstones. (6) Oncolitic grainstone (Er19/92) forming approximately spherical structures. (7) Organic rich grainstone/packstone layers bearing abundant early Famennian brachiopods typical for the orbelianus Zone of Abrahamyan (1957) and constituting the upper part of Interval 4.

Figure 6 .

 6 Figure 6. Lithostratigraphy of the Ertych section.

Figure 7 .

 7 Figure 7. Photomicrographs of thin sections from Interval 1 of the Ertych section. (1-2) Er19/1/1, peloidal bioclastic grainstone with shell fragments of brachiopods (1), and close-up of dasycladacean algae (2). (3-4) Er19/1/3, peloidal bioclastic grainstone (3) and close-up of iron dolomite (probably of late diagenesis) (4). (5-6) Er19/1/4, peloidal bioclastic grainstone with mollusk fragments and quartz grains (5) and close-up of a sea urchins spine (in transverse section) (6).

Figure 8 .

 8 Figure 8. Photomicrographs of thin sections from Interval 2 of the Ertych section. (1-2) Er19/1/5, sandstone (quartzwacke) with fish bones. (3) Er19/68, siliciclastic rock intermediate between quartzite and sandstone. (4) Er19/72, finegrained quartzite. (5) Er19/77 fine-grained bioturbated sandstone (quartz-wacke). (6) Er19/78, fine-grained sandstone with a lot of matrix (quartz-wacke). (7-8) Er19/98, coarse sandstone (quartz-wacke) with calcareous cement and a lot of fish bones, well-sorted bone layer (7) and close-up of the phosphatus concentration (8).

Figure 9 .

 9 Figure 9. Photomicrographs of thin sections from the lower part of Interval 4 of the Ertych section. (1-3) Er19/105, spectacular tentaculite packstone (1) that also contains bryozoans, fragments of bivalves (2), trilobites and brachiopod spines (3). (4-5) Er19/108, tentaculite packstone, a storm deposit that in ddition to tentaculites, also includes trilobite and fish bone fragments, (4) bryozoans and lithoclasts (5). (6-8) Er19/113 (6), Er19/119 (7) and Er19/124 (8) packstone with quartze grains and different fragments of brachiopods.

Figure 10 .

 10 Figure 10. Photomicrographs of thin sections from the upper part of Interval 4 of the Ertych section. (1-2) Er19/127, bioclastic grainstone (tempestite) mainly composed of different fragments of brachiopods, fish and trilobites. (3-4) Er19/133, bioclastic grainstone (tempestite), which also contains peloids, brachiopod spines, trilobite and dasycladacean algae. (5-6) Er19/143, bioclastic grainstone containing different fragments of brachiopods, dasycladacean algae (5) and ostracods (6). (7-8) Er19/176, coquina-bed, packstone with fragments of tentaculites, brachiopod spines (7) and ostracods (8).

Figure 11 .

 11 Figure 11. Photomicrographs of thin sections from the upper part of Interval 4 of the Ertych section. (1) Er19/192, grainstone with peloids (quite well sorted). (2) Er19/196, fine-grained quartzite, (well sorted). (3) Er19/198, finegrained sandstone (quartz-wacke). (4) Er19/241, fine-grained sandstone with matrix (quartz-wacke).

Figure 12 .

 12 Figure 12. Djravank section (lower part). (1) The mountain path originates from the ruins of the Ertych village and leads to the studied section; the arrow indicates the location of Interval 4. (2) Peloidal grainstone beds that constitute the base of the section (Dj19/10, Dj19/9 and Dj19/8). (3) A black shale (bl. sh.) layer cropping out below the layer Dj19/10, which is very rich in rhynchonellides and above which the atrypides disappear.

Figure 13 .

 13 Figure 13. Djravank section (upper part). (1). The muddy and shelly limestone layers Dj19/5 and Dj17/3, which constitute the lower part of Interval 4; (2). Middle part of Interval 4 represented by different kinds of carbonate rocks of which some are resistant and well-bedded (e.g., Dj 19/H) and the rest are less resistant, nodular and more shelly (e.g., Dj 19/I). (3). Successive layers of stromatoporoid which is indicated by an arrow and overlapped by an oncolitic layer (Dj17/2). (4). Marly and sandy nodular limestones cropping out at the top of Interval 4 that lithologically corresponds to

Figure 14 .

 14 Figure 14. Lithostratigraphy of the Djravank section.

Figure 15 .

 15 Figure 15. Photomicrographs of thin sections of Interval 1 of the Djravank section. (1-2) Dj19/10, peloidal bioclastic grainstone that displays strong bioturbation and quartz graines that partially replaced the host deposits (1) and close-up of a brachiopod spine (2). (3-4) Dj19/8, bioturbated coquina beds-grainstone containing shelly material (3) as well as fragments of cyanobacterial mats (4), and representing storm deposits. (5-6) Dj19/7, bioclastic grainstone, storm deposits comprising of brachiopod spines (of which the one of top right is encrusted by bryozoan and after reworked)(5), gastropods and fragment of dasycladacean algae (6).

Figure 16 .

 16 Figure 16. Photomicrographs of thin sections of intervals 1 and 4 of the Djravank section. Interval 1. (1-2) Dj19/6, grainstone facies with mixed peloid/brachiopod assemblage (1) that also includes ostracods, byozoans and gastropods (2). Interval 4. (3-4) Dj19/5, coquina-bed facies with fragments of stromatoporoids and cyanobacteria, ostracods (3) and a large brozoan (4).(5-6) Dj19/4, bioturbated wackestone with codiacean algae Umbella and sparite-filled fenestrae, (5) and close-up of one of those Umbella (6). (7-8) Dj17/13, bioclastic grainstone including fragments of brachiopods (7), crinoids and cyanobacteria (Girvanella) (8).

Figure 17 .

 17 Figure 17. Photomicrographs of thin sections of the upper part of Interval 4 of the Djravank section. (1-2) Dj17/12, bioclastic grainstone displaying burrows and including codiacean algae Umbella (1), ostracods and fragments of cyanobacterial mats (2). (3) Dj17/11, bioclastic peloidal grainstone, tempestite. (4) Dj17/3, lagunal facies with Umbella.

  apparently representing storm deposits. The layers Nv19/1 and Nv19/20 represent peloidal bioclastic grainstones, which are composed of brachiopod spines, gastropods (Fig.21.1, 21.4) and rare cyanobacterial mats (Fig.21.2). These grainstone layers are well-bedded and clearly distinct (Nv19/1-Nv19/20; Fig.19.2), whereas the layers cropping out above become more nodular and less resistant (Fig.19.3); this part of interval is composed of tempestites such as the layers Nv19/38

Figure 18 .

 18 Figure 18. Field photographs of the Noravank section. (1) Frasnian-Famennian siliciclastic-carbonate sequences exposed in a deep valley, on a slope of the Gnishik river, below the Noravank Monastery, which is covered by massive sandy limestones of Permian age. (2) Close view of the Frasnian base of the section (Nv19/1-Nv19/19), which is represented by well-bedded limestone beds (lower part of Interval 1). (3). Nodular limestones (Nv19/20) of Interval 1 wherein the last atrypide specimen was found. (4) The upper part (Nv19/74) of Interval 1. (5) Intercalations of shales and sandstones that represent the base of Interval 2.

Figure 19 .

 19 Figure 19. Noravank section. (1-2). Quartzite beds of Interval 3. (3). Slightly visible limestone layer (Nv19/218) that represents the base of Interval 4. (4). View of the top of Interval 4 consisting of Famennian marly and sandy limestones layers, which are unconformably overlain by sandy limestones of Permian age.

Figure 20 .

 20 Figure 20. Lithostratigraphy of the Noravank section.

  . 23.1-23.2), Nv19/109) and) are mainly bioturbated and clayey. Additionally, it is also worth mentioning that some of these sandstone layers, like the Nv19/109 contain also some fish bones (Fig.23.4). The single carbonate layer Nv19/134 of Interval 2 is described as bryozoan packstone of storm deposits and besides bryozoans, which are represented in this layer by at least two species, includes fragments of brachiopods, trilobites, ostracods and fish bones (Fig.24.1-24.2). The top of Interval 2 is represented by shale that it overlain by a massive interval of quartzites and sandstones, which together form the Interval 3. The lower and middle parts of this interval are mainly composed of massive quartzite whereas the upper part includes layers of sandstones and very thin layers of shales. The upper part of this interval is partly covered by scree which precludes the possibility to trace the beginning of the subsequent Interval. Thus, I consider the first limestone layer termed Nv19/218 (Fig.24.5-24.6) as the base of Interval 4, because it represents clearly different facies. The latter is a crinoidal grainstone layer. The Interval 4 (Figs.19.1, 20.4) chiefly consists of peloidal bioclastic grainstones, packstones and a single layer of oncolitic grainstone. The Nv17/4 is an oncolitic grainstone layer with peloides and bioclasts which form layered and approximately spherical structures (Fig.25.1-25.4) composed of cyanobacterial growth. This layer is quite distinct and differs from other carbonate layers cropping out both below or above by its spherical structure. Nv17/4 is overlapped by packstones (Nv17/1.bis; Fig.25.5-25.6) which contains a lot of sand grains, fragments of bivalves, brachiopod spines and bryozoans.

Figure 21 .

 21 Figure 21. Photomicrographs of thin sections from Interval 1 of the Noravank section. (1-2) Nv19/1, bioclastic peloidal grainstone with brachiopod spines, gastropods (1) and fragments of cyanobacterial mats (2). (3-4) Nv19/20, bioclastic peloidal grainstone (same facies as in Nv19/1). (5-6) Nv19/38, bioclastic peloidal grainstone, storm deposition, composed of different shell fragments of brachiopods, crinoids (5), lithoclasts that are reworked afterwards and cyanobacterial mats (6).

Figure 22 .

 22 Figure 22. Photomicrographs of thin sections from Interval 1 of the Noravank section. (1-4) Nv19/50, bioclastic peloidal grainstone (tempestite) with different fragments of brachiopods, crinoids (1), bryozoan (2), trilobite (3), fragments of cyanobacterial mats and tentaculites (4). (5-6) Nv19/60, bioclastic peloidal limestone with fragments of brachiopods (5) and a few codiacean algae Umbella (6). (7-8) Nv19/74, bioclastic peloidal grainstone with a few fragments of tentaculites (7), sea urchins and gastropods (8).

Figure 23 .

 23 Figure 23. Photomicrographs of thin sections from Interval 2 of the Noravank section. (1-2) Nv19/107, bioturbated clayey sandstone (quartz-wacke). (3-4) Nv19/109, bioturbated clayey sandstone (quartz-wacke) with a little phosphate concentration. (5-6) Nv19/111, bioturbated sandstone (quartz-wacke).

Figure 24 .

 24 Figure 24. Selected photomicrographs of thin sections from Intervals 2 and 4 of the Noravank section. (1-2) Nv19/134 (Interval 2), bryozoan packstone of storm deposit that also contains fragments of brachiopods and trilobites (2). (3-4) Nv19/137 (Interval 2), bioturbated clayey sandstone (lithic-wacke, storm deposit). (5-6) Nv19/218 (Interval 4), crinoidal grainstone.

Figure 25 .

 25 Figure 25. Interval 4 of the Noravank section. (1-4) Nv17/4, oncolitic grainstone with peloids and bioclast; polished slab (1) and photomicrographs of thin sections showing the oncolites, formed by layered and approximately spherical structures (2-3) composed of cyanobacterial growth (4).(5-6) Nv17/1. bis (Interval 4), packstone with a lot of sand (5),

  and hydrodynamically. The Interval 2 is chiefly composed of black shales, calcareous and clayey bioturbated sandstones (quartz-wacke) (and a single layer of bryozoan packstone observed only in the Noravank section). Hummocky cross-stratification (HCS) is observed within this interval in all three sections. The sandstones of Interval 2 consist of grains that are fine, irregularly shaped and connected each other by clayey material (e.g.,); thus, they are identified as lithicwacke. Some layers also contain fish bones. The total thickness of Interval 3 is ca. 25-30 m. It is mainly composed of quartzites in its lower and middle part and of sandstones and shales in its upper part. Two intercalating shale layers are observed between the thick quartzite beds of the lowermiddle part of this interval within the Ertych section; they contain abundant and well-preserved macro-plant remains (e.g., Fig.5.1). The ensuing Interval 4 is mainly distinguished by the alternation of different types of carbonate rocks including a layer of oncolitic limestone. The base of this interval in the Noravank section is represented by a distinct layer of crinoidal grainstone (Nv19/218), which is covered by black shales and bioclastic grainstones. In the middle part of this interval a distinct layer of oncolitic grainstone (Fig.24.1-24.4) crops out, which consists of

Figure 26 .

 26 Figure 26. Lateral correlation between the three studied sections.

  of massive quartzite and sandstone layers of Interval 3 indicate an aggradational sedimentary pattern accompanied with a HST. It is likely that these fine-grained quartzites were accumulated in a very shallow environment, more precisely in an inner ramp environment. However, the sandstones and shales cropping out in the upper part of this interval indicate a change in environment; most likely the shale layers developed in the upper part of this interval coincided with a TST and a trend in deepening. Unfortunately, no MFS was detected within this interval to indicate the layer which

Figure 27 .

 27 Figure 27. Sequence stratigraphic interpretation of the studied sections.

Figure 28 .

 28 Figure 28. Transverse serial sections of Ripidiorhynchus gnishikensis (Abrahamyan, 1959) (IGSNASRAGM 3926/PS 3032) from the Frasnian Cyrtospirifer subarchiaci-Cyprhoteorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000), Djravank section. Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 29 .

 29 Figure 29. Transverse serial sections of Ripidiorhynchus djravankensis n. sp. (IGSNASRAGM 3928/PS 3034) from the lowest Famennian Noravank Regional Stage, Djravank section. Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 30 .

 30 Figure 30. Scatter diagrams exhibiting the relation between shell width/ length (1), shell width/thickness (2), and shell

Figure 31 .

 31 Figure 31. Transverse serial sections of Cyphoterorhynchus koraghensis koraghensis (Reed, 1922) (IGSNASRAGM 3932/PS 3038) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000), Djravank section. Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 32 .

 32 Figure 32. Scatter diagrams of Cyphoterorhynchus koraghensis koraghensis(Reed, 1922). 1, Relation between shell

  3.6), argues its assignment to the Upper Devonian Atryparia (Costatrypa) Copper, 1973 rather than Middle

Figure 33 .

 33 Figure 33. Transverse serial sections of Desquamatia (Seratrypa) abramianae Komarov, 1992 (IGSNASRAGM 3938/PS 3044), from the Djravank section. Numbers refer to distances in mm from the tip of the ventral umbo. Scale bars: 5 mm.

  Material.-Twenty-three articulated specimens and four ventral valves: 12 articulated specimens and two ventral valves come from the Ertych section, 11 articulated specimens from the Djravank section, and two ventral valves from the Noravank section.Shell ontogeny.-Juveniles display a thinner shell with rectimarginate anterior commissure and semi-elliptic as well as very low tongue. Although not developed in juveniles, a sulcus occurs in older shells. Beak inclination angle does not change with age because juveniles also have an erect beak. The size distributions of Desquamatia (Seratrypa) abramianae during growth, as represented by the scatter plots of the widht/length, the width/thickness and the width/width of sulcus, show a continuous and progressive growth with no distinct grouping (Fig.34). The relative proportions of D. (S.) abramianae represented by sufficient material remain constant (linear regression: y = ax+b;

Figure 34 .

 34 Figure 34. Scatter diagrams of Desquamatia (Seratrypa) abramianae Komarov, 1992. 1, Relation between shell width and length. 2, Relation between shell width and thickness. Abbreviations: N, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value.

Figure 35 .

 35 Figure 35 . Transverse serial sections of Cyrtospirifer? sp. 2 (IGSNASRAGM 3945/PS 3051) from the lower Famennian Cyrtospirifer orbelianus Zone of Armenia, Djravank section. Numbers refer to distances in mm from the tip of the ventral umbo.

  Dorsal valve slightly inflated with flanks sloping gently towards lateral commissures, subquadrangular to subtrapezoidal in outline; highest at midlength, then decreasing gradually towards anterior margin; interarea linear, orthocline; fold low, well-delimited, inconspicuously originating from beak, round to flat-topped at front. Ornamentation of up to 16 rounded (5 ribs per 5 mm at anterior margin near sulcus and fold), simple, flattened, low ribs on each flank, becoming fainter towards posterolateral margins; in sulcus and on fold, up to 4-5 ribs, slightly narrower than those present on flanks; ribs slightly wider than interspaces on flanks; micro-ornament poorly preserved, only a few capillae observed in interspaces of the ventral valve.Ventral valve interior (Fig.36) with stout, long, extrasinal and markedly divergent dental plates, converging dorsally in umbonal region (as seen in transverse section); delthyrial plate short; central apical cavity large, poorly filled in by callus; lateral apical cavities slightly filled by callus; teeth massive, subrectangular in outline.

Figure 36 .

 36 Figure 36. Transverse serial sections of Cyrtospirifer sp. indet. 1 (IGSNASRAGM 3947/PS 3053) from the lower Famennian Cyrtospirifer orbelianus Zone of Armenia, Ertych section. Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 37 .

 37 Figure 37. Transverse serial sections of Cyrtospirifer pseudoasiaticus n. sp. (IGSNASRAGM 3949/PS 3055) from the lower Famennian Cyrtospirifer orbelianus Zone of Armenia, Ertych section. Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 38 .

 38 Figure 38. Scatter diagrams of Cyrtospirifer pseudoasiaticus n. sp. 1, Relation between shell width and length. 2, Relation between shell width and thickness. 3, Relation between shell width and width of sulcus. 4, Relation between shell width and length of dorsal valve. Abbreviations: N, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value.

Figure 39 .

 39 Figure 39. Transverse serial sections of Sinospirifer sp. 1 (IGSNASRAGM 3954/PS 3060) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone ofRzhonsnitskaya and Mamedov (2000) of the Ertych section (Fig.1). Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 40 .

 40 Figure 40. Transverse serial sections of Sinospirifer sp. 2 (IGSNASRAGM 3957/PS 3063) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpensis Zone ofRzhonsnitskaya and Mamedov (2000) (Fig.3) of the Ertych section (Fig.1). Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 41 .

 41 Figure 41. Transverse serial sections of Pseudocyrtiopsis areniensis n. sp. (IGSNASRAGM 3959/PS 3065) from the lower Famennian orbelianus Zone of Abrahamyan (1957) of the Djravank section (Fig. 1). Numbers refer to distances in mm from the tip of the ventral umbo.

Figure 42 .

 42 Figure 42. Scatter diagrams of Pseudocyrtiopsis areniensis n. sp. 1, Relation between shell width and length. 2, Relation between shell width and thickness. 3, Relation between shell width and width of sulcus. 4, Relation between shell width and length of dorsal valve. Abbreviations: N, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value.

  Ornamentation of up to 29 rounded (5 ribs per 5 mm at anterior margin near sulcus and fold), simple, flattened, low ribs on each flank, becoming fainter towards posterolateral margins; in sulcus and on fold, up to 25 ribs, increasing by bifurcation, much narrower than those present on flanks; ribs twice wider than interspaces on the entire shell; micro-ornament of fine capillae only on ribs with pustules on them and with closely spaced growth lines sometimes thickened as growth varices.Ventral valve interior (Fig.43) with relatively thin, long, intrasinal and slightly divergent dental plates, becoming subparallel more anteriorly, converging dorsally in umbonal region (as seen in transverse section); delthyrial thickening formed by accretion of strong apical callus from the internal faces of the dental plates and floor of ventral valve; delthyrial plate thin; lateral apical cavities posteriorly infilled; teeth relatively small, subcircular.

Figure 43 .

 43 Figure 43. Transverse serial sections of Pentagonospirifer abrahamyanae n. gen., n. sp. (IGSNASRAGM 3964/PS 3070), from the Djravank section. Numbers refer to distances in mm from the top of the ventral umbo.

  , who contributed greatly to the taxonomy and biostratigraphy of the Upper Devonian-Lower Carboniferous brachiopods of the Lesser Caucasus. Material examined.-Forty-eight articulated specimens and nine dissociated valves from the Ertych Regional Stage of the Ertych (nine articulated specimens and two ventral valves), Djravank (twenty-eight articulated specimens and five ventral valves) and Noravank (eleven articulated specimens and two ventral valves) sections. Shell ontogeny.-Examination of a few juvenile specimens shows that almost all superficial features (e.g., equibiconvex shell covered by numerous ribs, well-developed sulcus and fold;

Figure 44 .

 44 Figure 44. Scatter diagrams of Pentagonospirifer abrahamyanae n. gen., n. sp. 1, Relation between shell width and length. 2, Relation between shell width and thickness. 3, Relation between shell width and width of sulcus. 4, Relation between shell width and length of dorsal valve. Abbreviations: N, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value.

  delthyrial cover is unkown as only some of the remnants are partially preserved in one of the collected specimens(IGSNASRAGM 3975/PS 3081;; sulcus very narrow, shallow, originating from beak, well-defined, with gentle margins, round-bottomed at front; tongue very low, more or less rounded in outline, perpendicular to commissural plane. Dorsal valve wider than long, inflated with flanks sloping gently towards lateral commissures, subquadrangular to subtrapezoidal in outline; highest at about midlength or slightly posteriorly, then decreasing gradually towards anterior margin; interarea linear (up to 1.5 mm high), slightly concave, orthocline; fold well-delimited, low, relatively narrow, originating from beak, round-topped at front. Ornamentation of up to 30 rounded (generally 26-29; 4-5 ribs per 5 mm at anterior margin near sulcus and fold), low, flattened, simple ribs on each flank, becoming progressively fainter towards posterolateral margins; in sulcus and on fold, up to 15 ribs (generally 10-12) increasing by bifurcations and intercalations, narrower than those present on the flanks; ribs 2-2.5 wider than interspaces on the flanks and nearly as wide as interspaces in sulcus and on fold; micro-ornament of closely spaced growth lines sometimes thickened as growth varices (though it is worth mentioning that the preservation of current material does not permit to document the presence (or otherwise) of other structures (capillae, etc.).

Figure 45 .

 45 Figure 45. Transverse serial sections of Angustisulcispirifer arakelyani n.gen, n. sp. (IGSNASRAGM 3969/PS 3075) from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000), Noravank section. Numbers refer to distances in mm from the top of the ventral umbo. Scale bars: 5 mm.

Figure 46 .

 46 Figure 46. Scatter diagrams of Angustisulcispirifer arakelyani n. gen., n. sp. 1, Relation between shell width and length. 2, Relation between shell width and thickness. 3, Relation between shell width and width of sulcus. 4, Relation between shell width and length of dorsal valve. Abbreviations: n, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value.

(

  2018b: text-fig. 102) illustrated the internal morphology of her material by only one serial section showing only the ventral interior and thus further evidences are needed to point out other similarities and differences concerning internal morphology of these two species. The new species shares several similarities with two species recognized from the Famennian of Central Kara-Tau, namely Cyrtospirifer (C.) kursaensis Sidjachenko, 1962 and C. (C.) limatus

Figure 47 .

 47 Figure 47. Transverse serial sections of Tornatospirifer armenicus (Abrahamyan, 1974) (IGSNASRAGM 3977/PS 3083), Djravank section. Numbers refer to distances in mm from the top of the ventral umbo.

Figure 48 .

 48 Figure 48. Scatter diagrams of Tornatospirifer armenicus (Abrahamyan, 1974). 1, Relation between shell width and length. 2, Relation between shell width and thickness. 3, Relation between shell width and width of sulcus. 4, Relation between shell width and length of dorsal valve. Abbreviations: N, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value.

Figure 49 .

 49 Figure 49. Diversity and stratigraphic distribution of brachiopods of the Ertych section.

Figure 50 .

 50 Figure 50. Diversity and stratigraphic distribution of brachiopods of the Djravank section.

Figure 51 .

 51 Figure 51. Diversity and stratigraphic distribution of brachiopods of the Noravank section.

Figure 52 .

 52 Figure 52. Biochronostratigraphic framework and the correlation of three studies section based on the newly established brachiopod biozones and the biozonation schemes of Abrahamyan (1957) in Central Armenia and Rzhonsnitskaya and Mamedov (2000) in Nakhichevan.

Figure

  Figure 53. Biochronostratigraphic framework of the lower/middle Frasnian-lower Famennian sedimentary sequences in the Lesser Caucasus,

Figure 54 .

 54 Figure 54. Biostratigraphic distribution of brachiopods reported from the Frasnian-lower Famennian sedimentary sequences in the Lesser Caucasus that includes the described both in the current study and those which were known

Figure 55 .

 55 Figure 55. Biostratigraphic distribution of brachiopod species belonging to the order Orthotetida, Productia and Rhynchonellida reported from the Frasnian-lower Famennian sedimentary sequences in the Lesser Caucasus. Red color

Figure 56 .

 56 Figure 56. Biostratigraphic distribution of brachiopod species belonging to the orders Atrypida, Athyrida and Spiriferida, reported from the Frasnian-lower Famennian sedimentary sequences in the Lesser Caucasus. Red color indicates species which are known from Armenia based on the data ofAbrahamyan (1957Abrahamyan ( , 1974) ) andArakelyan (1964);

Figure 57 .

 57 Figure 57. The composition of brachiopod assemblages described in the Lesser Caucasus and represented by percentages on pie charts at the order level. (1) The Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis assemblage. (2) The lower Famennian Cyrtiopsis orbelianus-Cyrtiopsis armenicus assemblage.

Figure 59 .

 59 Figure 59. Paleobiogeographic distribution of the newly established genera (the paleomap redrawn and modified after Denayer and Hoçgör, 2014, based on the maps of Stampfli et al., 2002).

  Aramazdospirifer n. gen., Pentagonaspirifer n. gen., Tornatospirifer and the Frasnian Angustisulcispirifer n. gen likely include several other Famennian species described from Pamir (Tajikistan), Central Kazakhstan and the East European Platform, although the latter species are in need of a modern taxonomic reassessment (Fig.59). The new species of Pseudocyrtiopsis areniensis represents the first ever report of the genus Pseudocyrtiopsis Ma and Day (1999) in the lower Famennian strata of SAB. This discovery highlights an important radiation of this kind, since until now it was known only from China and possibly from Belgium.Ma and Day (2007) indicated that the genus Sinospirifer[START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF] first occurs in the lower Famennian, as observed in the Russian Platform, South China, southwestern USA (western North America) and possibly eastern

2 .

 2 The three studied sections (Ertych, Djravank and Noravank) have similar lithostratigraphic successions and contain shallow water mixed carbonate-siliciclastic deposits that were subdivided into four distinct intervals. It is likely that the Interval 1, composed mainly of bioclastic/peloidal grainstones and a few layers of tempestites, accumulated in an inner ramp environment at a time of high sea level, whereas the deposition of Interval 2, composed of bioturbated sandstones and black shales, took place on the median part of a ramp during a transgressive event. The Interval 3 is primarily composed of quartzites, sandstones and a few layers of shale; it displays an aggradational sedimentary pattern and reflects a HST, while the overlying Interval 4 represents a carbonate interval is composed at its base of grainstones or wackestones facies (depending on section); this Interval contains in its upper part, an oncolitic layer that was accumulated in a lagoonal environment and which indicates a dramatic sea level drop. This interval ends in our studied sections with grainstones/packstones, the composition of which suggests a deepening-upward (transgressive) trend.3. Twenty-six species of Rhynchonellide, Atrypide, Athyride and Spiriferide brachiopods are documented and described in detail. They constitute two distinct assemblages: the first one (Ripidiorhynchus gnishikensis-Angustisulcispirifer) is described from the Interval 1, which may be correlated with the Baghrsagh Regional Stage, whereas, the second one (Aramazdospirifer orbelianus-Tornatospirifer armenicus) is recovered from the Interval 4

  (6-10). IGSNASRAGM 3940/PS 3046 (Djravank section), almost complete specimenin ventral, dorsal, lateral, posterior and anterior views. (11-16). IGSNASRAGM 3941/PS 3047 (Djravank section), almost complete specimenin ventral, dorsal, lateral, posterior and anterior views (11-15), and close-up (16) of tubular ribs increasing by bifurcation and intercalation on the ventral valve. Scale bars: 10 mm (1-15), 2 mm (16).

(

  [11][START_REF]which is not the case of the new genus. The new genus is distinguished from the Famennian genus Dmitria Sidjachenko, 1961, by its well-developed sulcus and fold, its high and subogival tongue, its high ventral interarea and by the presence of numerous pustules developed on capillae. Internally, Tornatospirifer n. gen. mainly differs by its delthyrial plate, which[END_REF][13][14][15][16]. IGSNASRAGM 3952/PS 3058 (Djravank section), almost complete specimenin ventral, dorsal, lateral, posterior and anterior views (11-15), and close-up of the sulcus displaying the bifurcation of ribs (16). (19-21). IGSNASRAGM 3953/PS 3059 (Ertych section), poorly preserved articulated specimen in posterior view (19) and close-up close-up of the ventral interarea showing the pseudodeltidium in posterior and oblique lateral views (20-21). Scal bars: 10 mm (1-15, 19), 5 mm (18), 2 mm (20-21), 1 mm (16), 0.5 mm (17).

(

  [19][20][21][22][23][24][25][26]. IGSNASRAGM 3973/PS 3079, (Noravank section), almost complete specimenin ventral, dorsal, lateral, posterior, posterodorsal and anterior views (13-24), and close-up of the ventral interarea showing the remnants of a delthyrial cover of unknown origin (25-26). (27). IGSNASRAGM 3974/PS 3080 (Ertych section), incomplete specimen, close-up of the ventral interarea clearly displaying the delthyrial plate, though it is partly concealed by sediment. Scale bars: 10 mm (1-24), 2 mm (25, 27), 0.5 mm (26).

  3 O.D. Earth and History of Life, Royal Belgian Institute of Natural Sciences, rue Vautier 29, B 1000 Brussels, Belgium <bmottequin@naturalsciences.be> Running Header: Lower Famennian brachiopods from Armenia

  Repositories and institutional abbreviations.-All illustrated material is housed at the Geological Museum of the Institute of Geological Sciences of the National Academy of Sciences of Armenia, Yerevan (IGSNASRAGM/PS). The prefix PS indicates the laboratory of Paleontology and Stratigraphy. Part of the studied material is housed at the public paleontological collection of the University of Lille (USTL). The prefix RBINS is used for some specimens deposited at the Royal Belgian Institute of natural Sciences, Brussels. Specimens cited in Brice (1967) are stored de Paléontologie de la Faculté Libre des Sciences des Lille (Collection De Lapparent, Brice). The material studied by Erlanger (1993) is housed at the Borissiak Paleontological Institute of the Russian Academy of Sciences, Moscow and is calatogued under the prefix PIN and collection № 3744.

  cropping out in the Ertych, Djravank and Noravank sections of central Armenia allows us to recognize the presence of six rhynchonellide and one athyridide species. As rhynchonelliform brachiopods have a benthic mode of life and produce lecithotrophic larvae, their paleobiogeographic patterns have a potential to reveal past geographic boundaries and oceanographic connections, although

Figure 1 .

 1 Figure 1. Schematic geological map and distribution of the Upper Paleozoic sequences in the

Figure 2 .

 2 Figure 2. Biochronostratigraphic framework of the upper Frasnian-middle Famennian

Figure 4 .

 4 Figure 4. Transverse serial sections of Sartenaerus baitalensis(Reed, 1922) from the

Figure 5 .

 5 Figure 5. 1-10. Sartenaerus charakensis(Brice, 1967) from the lower Famennian

Figure 6 .

 6 Figure 6. Transverse serial sections of Sartenaerus charakensis(Brice, 1967) from the lower

Figure 7 .

 7 Figure 7. Transverse serial sections of Porthmorhynchus? sp. from the lower Famennian

Figure 8 .

 8 Figure 8. Gesoriacorostrum? sp. from the lower Famennian 'Cyrtospirifer' orbelianus Zone in

Figure 9 .

 9 Figure 9. Transverse serial sections of Gesoriacorostrum? sp. from the lower Famennian

Figure 10 .

 10 Figure 10. Greira transcaucasica Erlanger, 1993 from the lower Famennian 'Cyrtospirifer'

Figure 11 .

 11 Figure 11. Transverse serial sections of Greira transcaucasica Erlanger, 1993 from the lower

Figure 12 .

 12 Figure 12. Sharovaella? sp. from the lower Famennian 'Cyrtospirifer' orbelianus Zone of

Figure 13 .

 13 Figure 13. Transverse serial sections of Sharovaella? sp. from the lower Famennian

Figure 14 .

 14 Figure 14. Crinisarina pseudoglobularis sp. nov. from the lower Famennian 'Cyrtospirifer'

  3024 (Djravank section), partly exfoliated specimen in ventral, dorsal, lateral, posterior and anterior views. Scale bars: 5 mm (1-15, 19-28), 500 μm (16), 100 μm (17), 40 μm (18).

Figure 15 .

 15 Figure 15. Transverse serial sections of Crinisarina pseudoglobularis sp. nov. from the lower

Figure 16 .

 16 Figure 16. Scatter diagrams exhibiting the relation between shell width and length (in mm) of

Figure 17 .

 17 Figure 17. Scatter diagrams exhibiting the relation between shell width and thickness (in mm) of

Figure 19 .

 19 Figure 19. Late Devonian paleogeographic reconstruction of the Paleotethys ocean and its

Type species :

 species Spirifer orbelianus Abich, 1858. Other species: It is currently difficult to assign other species to Aramazdospirifer gen. nov. with certainty in the absence of taxonomical revisions of the diverse cyrtospiriferide fauna from the Famenian of the ex-USSR. Spirifer (Cyrtospirifer) aperturatus von Schlotheim sensu Nalivkin (1930) described in the Central Kara-Tau and along the headwaters of the Naryn river (Kazakhstan) likely belongs to the new genus, although the latter has a less globular shell, cubcircular tongue and lacks median and longitudinal elevations in sulcus and fold. It is worth nothing that the real aperturatus from Germany and the Franco-Belgian basin differs from

  Material examined.-Eighty articulated specimens, ten ventral and five dorsal valves from the marly/sandy limestones of the Ertych horizon of the Djravank (sixty articulated specimens and ten ventral valves), Noravank (type locality; twelve articulated specimens and four dorsal valves) and Ertych (eight articulated specimens and one dorsal valve) sections. Three articulated specimens in Abrahamyan's collection (IGSNASRAGM) from the Noravank section and two ventral valves from the Gyumushlug section (Nakhichevan).

  sulcus wide, shallow to moderately deep, originating from beak, widening and becoming deeper anteriorly, sulcus margins gentle. Sulcus bears a longitudinal and median elevation which inconspicuously originates in the posterior part of the valve; it widens, thickens and becomes more conspicuous anteriorly (highest and widest at the anterior margin); tongue high, perpendicular to commissural plane with its distal part sometimes bent dorsally, subogival in outline.Dorsal valve widerthan long, inflated with flanks sloping moderately to strongly towards lateral commissures, subquadrangular to subtrapezoidal in outline; highest in the anterior third of the valve, but gradually decreasing towards the anterior margin; interarea linear (up to 3 mm high), slightly concave, orthocline; fold well-defined, wide, moderately high, inconspicuously originating from beak, widening and becoming higher anteriorly, often bearing a longitudinal and median elevation starting from dorsal beak.Ornamentation of up to 35 rounded (generally 28-30, 5-6 ribs per 5 mm at anterior margin near sulcus and fold), simple, flattened, low ribs on each flank, becoming fainter towards posterolateral margins; in sulcus and on fold, up to 25 ribs, increasing by bifurcations, much narrower than those present on flanks; interspaces as wide as ribs on flanks, but wider than ribs in sulcus and on fold; micro-ornament of capillae both on ribs and in interspaces with concentric growth lines sometimes thickened as growth varices. Ventral valve interior with thin, long, intrasinal and divergent dental plates, becoming much less divergent to almost parallel more anteriorly, converging dorsally in umbonal region (as seen in transverse section); delthyrial plate well-developed, thick (particularly in large specimens); umbonal callus well-developed, central and lateral apical cavities large and filled in by callus; teeth relatively small, subrectangular. Dorsal valve interior with unsupported ctenophoridium composed of up to 33 well developed, relatively long lamellae; hinge plate divided; outer hinge plates slightly concave, crural bases dorsally convergent; spiral cones not preserved in the sectioned specimens.Variability.-The shell shape varies from almost globular forms with thickness exceeding as width and length, having narrower, shallow sulcus to transversely elongated wider forms with broad sulcus and relatively less inflated valves. The beak angle, the height of the longitudinal elevation and the number of ribs are also shifting.Ontogeny.-Juvenile forms differ from adults in having less inflated valves, straight beaks, shallower sulcus, weak fold, fainter ribs, inconspicuous elevations developed only anteriorly and the less convex delthyrial plate. The size distribution during growth represented by the length/width, thickness/width, width of sulcus/width and length of dorsal valve/width plots (Fig.6) shows a continuous and progressive growth with no distinct grouping. The relative proportions of Aramazdospirifer orbelianus represented by sufficient material remain constant (linear regression: y = ax+b; significant probability value: p < 0.001*** whatever the degree of development of individuals (Fig.6)). Moreover, the correlation is positive with width varying proportionally with length, thickness, width of sulcus and the length of dorsal valve. To complete the scatter plots, the measurements (in mm) of numerous individuals of Aramazdospirifer orbelianus are also presented in table 1 and figure 7. The length of the dorsal valve shows less dispersed values (Fig.7).

Figure 1 .

 1 Figure 1. Schematic geological map of the South-Armenian Block; distribution of the Upper Devonian-Lower Carboniferous deposits with localization of the sections containing

Figure 1 .

 1 Figure 1. Carte géologique schématique du Bloc Sud-Arménien; distribution des dépôts du Dévonien supérieur-Carbonifère inférieur avec localisation des coupes contenantAramazdospirifer orbelianus(Abich, 1858).

Figure 2 .

 2 Figure 2. Biostratigraphic scheme of the Lower Famennian of the Lesser Caucasus (Transcaucasus) correlated with the major lithostratigraphic units.

Figure 2 .

 2 Figure 2. Schéma biostratigraphique du Famennien inférieur de la partie méridionale du Petit Caucase (Transcaucasie) corrélé avec les principales unités lithostratigraphiques.

Figure 3 .

 3 Figure 3. Aramazdospirifer orbelianus (Abich, 1858). 1-6 and 18-20. Almost complete specimen (IGSNASRAGM 3895/PS 3001) from the Djravank section in ventral, dorsal, posterior, lateral, posterodorsal and anterior views (1-6), close-up of micro-ornament (capillae and growth lines) on dorsal valve (close to anterior margin; 18-20). 7-8. Incomplete specimen (IGSNASRAGM 3896/PS 3002) from the Noravank section, close-up of the ventral interarea (delthyrium; 7). 9-14. Almost complete specimen (IGSNASRAGM 3897/AB97/48; neotype, Noravank section) in ventral, dorsal, posterodorsal, posterior, anterior and lateral views. 15-22. Almost complete specimen (IGSNASRAGM 3898/PS 3004) from the Ertych section in ventral, dorsal, lateral, posterior and anterior views. 23-27. Almost complete juvenile specimen (IGSNASRAGM 3899/PS 3005) from the Djravank section in ventral, dorsal, posterior, anterior and lateral views. Scale bars: 10 mm (1-6, 9-14, 15-17, 21-27), 2 mm (7), 5 mm (8), 200 μm (18), 400μm (19), 500 μm (20).

Figure 3 .

 3 Figure3. Aramazdospirifer orbelianus(Abich, 1858). 1-6 et 18-20. Spécimen quasicomplétement (IGSNASRAGM 3895/PS 3001) de la coupe de Djravank en vues ventrale, dorsale, postérieure, latérale, postérodorsale et antérieure (1-6), vue de détail de la microornementation (capillae et lignes de croissance) sur la valve dorsale (proche de la marge antérieure 18-20). 7-8. Spécimen incomplet (IGSNASRAGM 3896/PS 3002) de la coupe de Noravank, vue de détail de l'interarea ventrale (delthyrium; 7). 9-14. Spécimen articulé quasi complet (IGSNASRAGM 3897/AB97/48; néotype, coupe de Noravank) en vues ventrale,

Figure 4 .

 4 Figure 4. Aramazdospirifer orbelianus (Abich, 1858) the Ertych section. The arrows indicate the anterior margin. 1-7. Almost complete specimen (RBINS a13459) in ventral (muscle field and long intrasinal dental plates are visible), dorsal and anterolateral views, close-up of the pseudodeltidium, and detail of the capillate micro-ornament observed in sulcus near the anterior margin. 8-11. Incomplete specimen (RBINS a13460) in ventral (slightly inclined showing the intrasinal dental plates and the median fold in sulcus) and dorsal views, close-up of the myophragm, and detail of the capillate micro-ornament observed on the left flank of the dorsal valve. 12-13. Poorly preserved articulated specimen (RBINS a13461), view of the ventral areashowing the pseudodeltidium and close-up of the latter. Scale bars: 10 mm (1-3, 8-9), 5 mm (4-5, 10, 13), 5 mm (12), 2 mm (11), 1 mm (6, 7).

Figure 4 .

 4 Figure 4. Aramazdospirifer orbelianus (Abich, 1858) de la coupe d'Ertych. Les flèches indiquent le bord antérieure. 1-7. Spécimen quasi complet (RBINS a13459) en vue ventrale (les régions du muscle et des longues plaques dentaires intrabasinales sont visibles), vues dorsale et antérolatérale, vue de près du pseudodeltidium et détail de la micro-ornamentation capillate observée au niveau du sulcus près de la marge antérieure. 8-11. Spécimen incomplet (RBINS a13460) en vues ventrale (légèrement inclinée montrant les plaques dentaires intrasinales et le plissement médian au niveau du sulcus) et dorsale, vue de détail du myophragme, et détail de lamicro-ornementation capillate observée sur le côté gauche de la valve dorsale. 12-13. Spécimen articulé mal préservé (RBINS a13461), vue de la région ventrale montrant le pseudodeltidium et vue de près de ce dernier. Echelles:10 mm (1-3, 8-9), 5 mm (4-5, 10, 13), 5 mm (12), 2 mm (11), 1 mm (6, 7).

Figure 5 .

 5 Figure 5. Transverse serial sections of Aramazdospirifer orbelianus (Abich, 1858) from the Djravank section. Numbers refer to distances in mm from the tip of the ventral umbo. Scale bars: 5 mm.

Figure 5 .

 5 Figure 5. Coupes sériées transversales de Aramazdospirifer orbelianus (Abich, 1858) de la coupe de Djravank. Les chiffres se réfèrent à des distances en mm de l'extrémité de l'umbo ventral. Echelle: 5 mm.

Figure 6 .

 6 Figure 6. Scatter diagrams of Aramazdospirifer orbelianus (Abich, 1858). Abbreviations: N, number of specimens measured; p: probability value; r: coefficient of correlation. 1, Relation between shell width and length. 2, Relation between shell width and thickness. 3, Relation between shell width and width of sulcus. 4, Relation between shell width and length of dorsal valve.

Figure 6 .

 6 Figure 6. Diagrammes de dispersion d'Aramazdospirifer orbelianus(Abich, 1858). Abréviations: N, nombre de spécimens mesurés; p: valeur de probabilité; r: coefficient de corrélation. 1, Relation entre la largeur et la longueur de la coquille. 2, Relation entre la largeur et l'épaisseur de la coquille. 3, Relation entre la largeur de la coquille et la largeur du sulcus. 4, Relation entre la largeur et la longueur de la valve dorsale.

Figure 7 .

 7 Figure 7. Measurements and ratios in mm of Aramazdospirifer orbelianus (Abich, 1858) Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

Figure 7 .

 7 Figure 7. Mesures et rapports en mm de Aramazdospirifer orbelianus(Abich, 1858)

Table 1

 1

	), slightly wider than long, rounded subtriangular in outline, sharply dorsibiconvex; widest
	at midlength or slightly anteriorly to it, highest near umbones; anterior margin slightly rounded to
	emarginate; anterior commissure uniplicate, serrate.
	Ventral valve gently inflated in both lateral and posterior profiles with flanks sloping gently
	towards lateral commissures; highest near umbo then decreasing progressively towards anterior
	margin; umbo prominent, inflated; beak long, straight; foramen unobserved; sulcus wide, shallow to
	moderately deep, imperceptibly originating in the umbonal area, flat-to slightly round-bottomed at
	front; tongue high and wide, with sharp borders, subtrapezoidal in outline, perpendicular to
	commissural plane or slightly bent dorsally.
	Dorsal valve inflated, regularly curved in posterior and lateral profile views with convex
	flanks sloping moderately to strongly towards lateral commissures; highest in the anterior third of
	the valve margin, progressively decreasing towards posterior margin; fold low to moderately high,
	starting more posteriorly to midlength, more developed anteriorly, flat-topped at front.

Table 1 .

 1 Measurements in mm and ratios of Ripidiorhynchus gnishikensis

			) with thin, long dental plates converging ventrally; teeth
	massive, subrectangular in outline; central apical cavity wide. Dorsal valve interior (Fig. 28) with
	low and very short septum; septalium deep, Y-shaped and covered anteriorly; hinge plate united.
	Material.-Nine articulated specimens and four ventral valves from the Ertych (four articulated
	specimens and two ventral valves) and Djravank (five articulated specimens and two ventral valves)
	sections.
		W	L	T	Ws	L/W	T/W	Ws/W
	Number of individuals	9	9	9	9	9	9	9
	Mean value	16.52	14.13	12.26	8.59	0.86	0.74	0.52
	Standard deviation	0.98	1.2932	1.1349	0.5326	0.0549	0.0299	0.0335
	Standard error±	±0.3274	±0.431	±0.3783	±0.1775	±0.0183	±0.0099	±0.0112
	Min	15.1	13	11	7.9	0.78	0.7	0.49
	Max	17.9	16.2	13.7	9.3	0.93	0.77	0.58

Table 2 .

 2 Measurements in mm and ratios of Ripidiorhynchus djravankensis n. sp. Abbreviations: W-width of the shell,

	mm) of numerous individuals of R. djravankensis n. sp. are represented in Table 2.
		W	L	T	Ws	L/W	T/W	Ws/W
	Number of individuals	29	29	29	29	29	29	29
	Mean value	15.59	12.99	11.22	8.09	0.83	0.72	0.52
	Standard deviation	1.5679	1.7159	2.0184	0.8526	0.0586	0.0931	0.0339
	Standard error±	±0.2912	±0.3186	±0.3748	±0.1583	±0.0109	±0.0173	±0.0063
	Min	12.5	10.5	7.2	7	0.74	0.55	0.47
	Max	19.5	17.1	14.7	11.1	0.97	0.91	0.58
	L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

  -6 ribs in sulcus, 5-7 ribs on fold; one pair (occasionally two) of ribs generally developed on the flanks of the fold and sulcus; ribs wider than interspaces; growth lines numerous.

	margins, 4
	Occurrence.-In Armenia, recent samplings revealed the presence of this species only in the
	Frasnian sequences. It now appears obvious that the reports of this species by Arakelyan (1952) and
	Arakelyan et al. (1975) within the lower Famennian of the Gyumushlugh section have to be
	reinterpreted in the light of the current definition of the Frasnian-Famennian boundary although it is
	currently not located with precision in Armenia in the absence of the diagnostic conodonts. Reed's
	reported from the lower Famennian Elets Horizon (central Russia), by its more species was reported in the Frasnian of Nakhichevan by Rzhonsnitskaya and Mamedov (2000) and
	inflated shell, well-developed sulcus and fold as well as high tongue. Mirieva (2010).
	R. djravankensis n. sp. is differing from R. chencinensis Sokiran, 2006 reported from the
	uppermost Givetian of the Holy Cross Mountains (Poland), by its higher and wider tongue, by the Description.-Shell medium-sized, attaining up to 27 mm in width, 24.3 mm in length and18.5 in
	presence of one pair of faint ribs developed on the flanks of the fold and on the margins of the thickness (Table 3), transversally ovate in outline, wider than long; widest and highest at about
	sulcus, and the absence of a strong median rib in sulcus and of two opposed ribs on fold which is midlength; strongly dorsibiconvex; anterior margin emarginate; anterior commissure uniplicate and
	commonly observed in R. chencinensis. serrate.
	R. djravankensis n. sp. is separable from R. gnishikensis (Abrahamyan, 1959), which was Ventral valve slightly inflated with flanks sloping gently towards lateral commissures; beak
	recently illustrated by Pakhnevich in Alekseeva et al. (2018a), by its larger and transversally ovate suberect; foramen minute, permesothyrid; sulcus wide, shallow to moderately deep, generally well-
	shell (see above). defined by sulcus bounding ribs, imperceptibly starting from midlength or more anteriorly,
	deepening gradually towards anterior margin, flat-to round-bottomed at front; tongue high,
	Genus Cyphoterorhynchus Sartenaer, 1965 perpendicular to commissural plane, subtrapezoidal in outline.
	Dorsal valve strongly inflated, regularly and strongly curved in posterior and later profile
	Type species.-Uncinulus (Uncinulina) koraghensis Reed, 1922. views with flanks sloping strongly towards lateral commissures, highest at about midlength then
	decreasing progressively towards anterior margin; umbo inflated, prominent, protruding beyond
	Cyphoterorhynchus koraghensis koraghensis (Reed, 1922) posterior margin; beak covering the delthyrium; fold low, more defined anteriorly, wide,
	Plate 2.1-2.15; Figures 31-32; Table 3 inconspicuously originating from midlength or slightly posteriorly to it, flat-topped at front.
	Ornamentation of coarse, angular ribs, originating from beaks; ribs in sulcus and on fold
	1902 Rhynchonella, species; Hudleston, p. 14, pl. 3, fig. 10a-c. larger than those present on flanks; 10-13 ribs on flanks becoming fainter towards posterolateral
	1911 Rhynchonella (Camarotoechia) cf. Omaliusi Gosselet; Reed, p. 104, pl. 8, figs. 2, 2a.

Table 3 .

 3 2, Relation between shell width and thickness. 3, Relation between shell width and width of sulcus. Measurements in mm and ratios of Cyphoterorhynchus koraghensis koraghensis

	Abbreviations: n, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant
	probability value.

Table 4 .

 4 Measurements

		W	L	T	L/W	T/W
	Number of individuals	23	23	23	23	23
	Mean value	25.5	25.7	16.4	1.01	0.64
	Standard deviation	6.42	5.9774	4.706	0.05	0.0756
	Standard error±	±1.3388	±1.2464	±0.981	±0.0104	±0.0158
	Min	12.5	14	7	0.95	0.52
	Max	39.6	37.7	27.9	1.12	0.76

in mm and ratios of Desquamatia (Seratrypa) abramianae Komararov, 1992. Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell.

Table 5

 5

), wider than long, ventribiconvex (rarely equibiconvex), rounded transverse in outline with obtuse cardinal extremities; hinge line narrower than widest, anterior margin emarginate; anterior commissure uniplicate; fold and sulcus relatively wide; tongue high, subogival to subcircular in outline; micro-ornament of closely spaced capillae occurring both on ribs and in interspaces and numerous pustules developed on capillae; dental plates divergent; delthyrial plate well-developed; teeth stout; ctenophoridium unsupported; dental sockets shallow; crural spiralia oriented posterolaterally.

Table 5 .

 5 Measurements

		W	L	T	Ws	dL	L/W	T/W	Ws/W	W/dL
	Number of individuals	24	24	24	24	24	24	24	24	24
	Mean value	27.6	18.5	18.9	10.5	17.6	0.67	0.68	0.38	0.64
	Standard deviation	1.92	1.5887	1.94	0.79	1.2771	0.0365	0.04	0.2636	0.021
	Standard error±	±0.3922 ±0.324	±0.3967	±0.16	±0.26	±0.007	±0.008	±0.0048	±0.0042
	Min	24	15.2	14.5	9.2	15	0.61	0.6	0.35	0.6
	Max	30	21.5	21.2	12	19.5	0.72	0.75	0.43	0.67

in mm and ratios of Cyrtospirifer pseudoasiaticus n. sp. Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

  based on its rounded transverse outline, ventribiconvex profile, apsacline and triangular ventral interarea, welldeveloped fold and sulcus bearing bifurcating ribs, flanks ornamented by low and flattened ribs, the type of micro-ornament (composed of capillae occurring both on ribs and in interspaces, and bearing numerous pustules), long dental plates extrasinal or positioned at sinal border and its well-

developed delthyrial plate. However, it is worth noting that our specimens display short hinge line, obtuse cardinal extremities and a pseudodeltidium formed by several distinct plates, features which are not frequently observed in cyrtospiriferids. We herein provide a comparison of C. pseudoasiaticus n. sp. with other Cyrtospirifer representatives but only with those which are described regarding to current standards as previously several species were lumped into the genus

  occurring in the upper Frasnian of USA by its comparatively short hinge line, lack of sharply extended cardinal extremities, type of pseudodeltidium and well-developed micro-ornament. It should be emphasized . differs by the presence of capillae on ribs and in interspaces whereas Sokiran's species devoid capillae. Internally, the new species is differing by its shorter delthyrial plate and smaller teeth. It is . pseudoasitaticus n. sp. differs externally from C. schelonicus[START_REF] Nalivkin | Brakhiopody glavnogo devonskogo polya[END_REF] as illustrated bySokiran (2006) from the middle Frasnian of East European Platform (EEP) by its smaller size, relatively short hinge line and by the lack of markedly extended cardinal extremities.

	pertinent to remind here that Sokiran (2013) erected her species based on the specimens, which
	were previously identified as Spirifer disjunctus (Sowerby, 1840) (e.g., Murchison et al., 1845;
	Nalivkin, 1947; Ljaschenko, 1959).
	Sinospirifer sp. 1
	Plate 7.1-7.13; Figure
	It is difficult currently to compare the new species with other cyrtospiriferids described in
	the EEP by means of pseudodeltidium and micro-ornament as the latter features are rarely preserved
	in the EEP material.

that internally C. pseudoasitaticus n. sp. is differing by its unsupported ctenophoridium, whereas the latter is sometimes supported in Stainbrook's species.

C. pseudoasitaticus n. sp. is externally separable from C. thalattodoxa

[START_REF] Crickmay | Discrimination of late Upper Devonian[END_REF]

as revised by

[START_REF] Ma | Revision of North American and selected Eurasian Late Devonian (Frasnian) species of Cyrtospirifer and Regelia (Brachiopoda)[END_REF]

from the middle Frasnian of Canada and USA by its deeper sulcus, straight beak, subogival to subcircular tongue round-topped at front and the type of pseudodeltidium. Moreover, the micro-ornament of the new species differs by the presence of capillae both on ribs and in interspaces whereas the latter is not observed in C. thalattodoxa.

Internally, the new species is readily distinguished by its smaller teeth, thinner dental plates and by the absence of strong apical of callosities in the ventral interior.

C. pseudoasitaticus n. sp. is separable from C. disjunctus

[START_REF] Sowerby | On the distribution and classification of theolder or Paleozoic deposits of the North of Germany and Belgium and their comparison with formations of the same age in the British Isles[END_REF]

sensu Sokiran (2013), by its smaller size, lack of sharply extended cardinal extremities and bifurcating ribs on flanks. Moreover, the micro-ornament of C. disjunctus consists of densely spaced concentric growth lines, whereas only a few concentric growth lines are observed in C. pseudoasitaticus n. sp. It is difficult to compare the internal morphology of these species as Sowerby (1840) did not show his serial sections. The new species may be distinguished from C. vjacheslavi Sokiran, 2013 occurring in the middle Frasnian of EEP by its transversely elongated shell, obtuse cardinal extremities, higher ventral interarea, straight beak and non-bifurcating ribs on flanks. Moreover, C. pseudoasitaticus n. spCInternally, the new species differs by its thin dental plates, smaller teeth and unsupported ctenophoridium.

C. pseudoasitaticus n. sp. is distinguishable from C. rudkinensis Ljaschenko, 1959 sensu

Sokiran (2006)

from the middle Frasnian of EEP by its smaller size, relatively short hinge line, lack of sharply extended cardinal extremities, high ventral interarea and wide delthyrium. Internally, the new species differs by its unsupported ctenophoridium and small teeth.

The new species is separable from C. mylaensis

Sokiran, 2006

from the middle Frasnian of EEP by its smaller size, less globular shell outline, obtuse cardinal extremities, relatively high fold and by the presence of pustules developed on capillae both on ribs and in interspaces. The most significant internal difference is the presence of strong callosities developed in central apical cavity of Sokiran's species, whereas the apical cavity of our material is poorly filled in.

Genus Sinospirifer

[START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF]

Type species.-Spirifer verneuili var. subextensus

Martelli,1902

Table 6 .

 6 Measurements in mm and ratios of Sinospirifer sp. 1. Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

		W	L	T	Ws	dL	L/W	T/W	Ws/W	W/dL
	Number of individuals	6	6	6	6	6	6	6	6	6
	Mean value	34.1	20.57	19.27	16	0.6	0.58	0.47	0.31	0.47
	Standard deviation	4.637	3.65	2.5696	3.4641	0.033	0.1616	0.05	0.054	0.05
	Standard error±	±2.677	±2.107	±1.4836	±2.01	±0.0189	±0.09	±0.0287	±0.312	±0.0287
	Min	29	16.4	16.9	12	0.57	0.44	0.41	0.26	0.41
	Max	38.1	23.2	22	18	0.63	0.76	0.51	0.37	0.51

  Description.-Shell medium-sized (attaining 41.1 mm in width, 23.2 mm in length and 22.5 mm in thickness), wider than long, equibiconvex, transversely elongated in outline; widest at hinge line;

	highest more posteriorly to midlength; cardinal extremities acute; anterior margin emarginate;
	anterior commissure uniplicate.
	Ventral valve inflated with convex flanks sloping steeply towards lateral commissures;
	highest in the posterior third of the valve, then decreasing progressively towards anterior margin;
	umbo inflated, large and prominent; beak and foramen unobserved; interarea triangular, moderately
	high, apsacline; sulcus shallow to moderately deep, originating from beak, with rounded lateral
	boundaries, round-bottomed at front; tongue wider than high, low to moderately high, subcircular to
	subogival in outline.
	Ventral interior (Fig. 40) with greatly thickened, extrasinal and divergent dental plates
	converging dorsally in umbonal region (as seen in transverse section) and extending up to 35% of
	the valve length; delthyrial thickening formed by accretion of strong apical callus from the internal
	faces of the dental plates and floor of ventral valve; delthyrial plate long, thick; central and lateral
	apical cavities infilled by stout callosity; teeth stout.
	Dorsal valve interior (Fig. 40) with unsupported ctenophoridium consisting of relatively

Dorsal valve inflated with flanks sloping moderately towards lateral commissures, subtrapezoidal in outline; highest in the anterior third of the valve, then progressively decreasing towards anterior margin; interarea linear, flat, orthocline; fold low, relatively wide, originating from beak, round-topped at front. Up to 28 simple, low ribs on flanks with top rounded; interspaces narrower than ribs; in sulcus and on fold, up to 11 ribs narrower than those on flanks, increasing by bifurcation; microornament poorly preserved, only a few capillae persist in interspaces and on ribs of the right flank of dorsal valve (Pl. 7.15). short lamellae; dental sockets shallow; hinge plates divided; crural bases dorsally convergent; spiralia unobserved.

Table 7 .

 7

		W	L	T	Ws	dL	L/W	T/W	Ws/W	W/dL
	Number of individuals	24	24	24	24	24	24	24	24	24
	Mean value	32.08	26.11	25.4	14.3	21	0.81	0.79	0.44	0.66
	Standard deviation	3.0778	2.4661	2.2571	2.5866	1.765	0.038	0.05	0.45.	0.034
	Standard error±	±0.6283	±0.503	±0.4607	±0.528	±0.36	±0.0076	±0.01	±0.009	±0.007
	Min	27.9	23.2	21.9	10.5	18.9	0.71	0.72	0.36	0.61
	Max	37.1	30.2	29.2	19	24.3	0.88	0.9	0.51	0.77

Table 7 .

 7 Measurements in mm and ratios of Pseudocyrtiopsis areniensis n. sp. Abbreviations: W-width of the shell, Llength of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

  Etymology.-Pentagonus, a, um (Latin): five-angled; spirifer is a common suffix used in the spiriferid group. The name draws attention to the pentagonal ventral valve of the genus.Remarks.-Pentagonospirifer n. gen. is assigned to the Subfamily Cyrtospiriferinae (Cyrtospiriferidae) on the basis of its wide hinge line, high interarea and acute cardinal extremities.The new genus resembles to some extent some representatives of the lower Famennian genus Sinospirifer[START_REF] Grabau | Devonian Brachiopoda of China, I: Devonian Brachiopoda from Yunnan and other districts in South China: China Geological Survey[END_REF] by its wide winge line, acute cardinal extremities, development of a massive apical callus in the ventral interior and its unsupported ctenophoridium; however, Pentagonospirifer n. gen. has a higher ventral interarea, a minute foramen near the apex, more ribs in sulcus and on fold and pustules developed only on capillae. Internally, the most significant It is worth noting that the internal structure of Wenjukovispirifer is not known; therefore, further comparison is hampered. Nevertheless,Oleneva (2016) did mention the presence of a ventral septum (=myophragm?) in the ventral interior of Wenjukovispirifer, which was not observed in Pentagonospirifer n. gen. Moreover, no strong apical callus on the delthyrial plate is mentioned for Wenjukovispirifer, a feature observed in Pentagonospirifer.Pentagonospirifer n. gen. mainly differs by the presence of strong apical callosity developed on the delthyrial plate.Pentagonospirifer n. gen. displays many external similarities (e.g. rounded subpentagonal outline, acute cardinal extremities, widest at hinge line, well-developed sulcus and fold with ribs fainter than those on flanks) with the lower Famennian genus Pripyatispirifer[START_REF] Pushkin | Pripyatispirifer, a new Lower Famennian genus from Belarus[END_REF] differs by its larger shell size, high ventral interarea and by its minute apical foramen. Besides, the new genus differs by its micro-ornament composed of capillae with pustules on them as Pripyatispirifer representatives lack plicae and pustules on ribs. Although, it is difficult to compare precisely the internal morphology of these genera as[START_REF] Pushkin | Pripyatispirifer, a new Lower Famennian genus from Belarus[END_REF] did not illustrate transverse sections but based onPushkin's illustration (1996, p. 47, fig. 2), the cardinal process of Eodmitria is papillose. It is worth emphasizing that both genera have quite similar internal morphologies, with the exception of dispositon of dental plates, which are intrasinal in the new genus, while Brice's genus has extrasinal ones. Pentagonospirifer n. gen. is distinguished externally from Pseudocyrtiopsis Ma and Day, 1999 from the lower Famennian of South China, by its larger and more inflated shell (due to the greater thickness of the dorsal valve), its bifurcating ribs in sulcus and on fold, its finer and more numerous ribs on flanks, as well as the lack of capillae that are developed in the interspaces of Pseudocyrtiopsis representatives. Internally, Pentagonospirifer n. gen. mainly differs by the presence of a strong apical callosity developed on the delthyrial plate and by its unsupported ctenophoridium.Pentagonospirifer n. gen. differs from Plicapustula Ma and Day, 2007, from the lower Famennian of South China and North America, by its more inflated and transversely elongated shell, well-developed pseudodeltidium with a minute foramen near the apex, bifurcating ribs across the whole width of sulcus and by the presence of capillae on ribs. Moreover, no strong apical callus on the delthyrial plate is mentioned for Plicapustula, a feature observed in Pentagonospirifer n.Holotype.-An almost complete articulated specimen that is partly covered by encrusters in itsDiagnosis.-Shell medium-sized (up to 36.7 mm in width, 34.1 mm in length, 29.2 mm in thickness) (Table8), wider than long, equibiconvex to ventribiconvex, widest at hinge line, highest at about midlength, with acute cardinal extremities; anterior margin emarginate; anterior commissure uniplicate; ventral interarea triangular, high, apsacline; pseudodeltidium with distinct, stacked sets of growth lamellae and with a minute, ovate foramen positioned apically; dorsal fold and ventral sulcus wide, and well-defined; tongue high, subtriangular to subcircular in outline; ribs numerous, usually simple on flanks, increasing by bifurcation in sulcus and on fold; microornament of capillae with pustules on them and closely spaced growth lines; dental plates long, extending to about 30% of the shell length, slightly convergent, diverging dorsally in the umbonal region, always intrasinal; delthyrial thickening is formed by a development of strong apical callus on delthyrial plate, around dental plates and floor of ventral valve; ctenophoridium unsupported, slightly convex, with numerous vertical lamellae. , high, generally slightly concave (occasionally perpendicular to commissural plane) well-defined; delthyrium wide, covered by a pseudodeltidium for most of its height, the latter being formed by distinct, stacked sets of growth lamellae; foramen minute, ovate, near the apex; sulcus relatively wide, shallow to moderately deep, originating from beak, with rounded lateral boundaries, round-to flat-bottomed at front; tongue high, perpendicular to commissural plane or slightly bent dorsally, subtriangular to subcircular in outline. Dorsal valve wider than long, strongly inflated, with flanks sloping moderately towards lateral commissures, subtrapezoidal in outline; highest in the anterior third of the valve (occasionally near midlength at the juvenile growth stages), but progressively decreasing towards anterior margin; interarea linear, flat to slightly concave, orthocline; fold moderately high to high, wide, originating from beak, round-topped at front.

	Pripyatispirifer Pentagonospirifer abrahamyanae new species
	Plate 9, Figures 43-44; Table 8
	Description.-Shell medium-sized, wider than long, generally equibiconvex to slightly
	ventribiconvex, rounded subpentagonal in outline, widest at hinge line, highest at about midlength;
	sulcus (IGSNASRAGM 3928/PS3073; Plate. 9.11-9.18), lower Famennian orbelianus Zone of cardinal extremities acute; anterior margin emarginate; anterior commissure uniplicate.
	Occurrence.-Lower Famennian of Armenia.
	Djravank section (7 km southeast from Areni, Vayots Dzor Province, Central Armenia (Fig. 1)). Ventral valve strongly inflated, with convex flanks sloping steeply towards lateral

, Table 1. Genus Pentagonospirifer new genus Type species.-Pentagonospirifer abrahamyanae n. gen., n. sp., by monotypy.

Diagnosis.-Shell medium-sized, equibiconvex to ventribiconvex, with acute to slightly mucronate cardinal extremities. Widest at hinge line. Ventral interarea triangular, high, variably concave, apsacline. Pseudodeltidium composed of several distinct plates, with apical foramen. Dorsal fold and ventral sulcus wide, well-defined. Ribs numerous, usually simple on flanks, increasing by bifurcation in sulcus and on fold. Micro-ornament of capillae with pustules on them and closely spaced growth lines. Dental plates long, always intrasinal. Delthyrial thickening is formed by a development of strong apical callus on delthyrial plate, around dental plates and floor of ventral valve. Ctenophoridium unsupported. difference concerns the dental plates that are intrasinal and devoid of thickening in Pentagonospirifer n. gen., whereas Sinospirifer possesses greatly thickened extrasinal dental plates Externally, Pentagonospirifer n. gen. is close to Wenjukovispirifer Oleneva, 2016, known from the Famennian of EEP, by its rounded subpentagonal outline, inflated shell, high ventral interarea, well-developed sulcus and fold, ornamentation composed of simple, low ribs separated by narrower interspaces; however, the new genus is distinguished by its relatively equibiconvex lateral profile, its pseudodeltidium with distinct, stacked sets of growth lamellae and its minute foramen developed apically.

The new genus may be distinguished from the late Givetian to early Famennian? genus Cyrtospirifer

Nalivkin in Frederiks, 1924

, sensu Ma and Day 2003, by its more longitudinally elongated shell, the presence of a robust pseudodeltidium and its micro-ornament. Internally, appears to be trilobed, which is quite an unusual case, thus different from that of Pentagonospirifer n. gen.

Pentagonospirifer n. gen. differs mainly from Eodmitria

[START_REF] Brice | Eodmitria, genre nouveau de brachiopode Cyrtospiriferidae du Frasnien Inférieur et Moyen[END_REF]

, known from the lower-middle Frasnian of Western Europe (Belgium, France and Germany) and Turkey, by its more inflated shell, high ventral interarea and well-defined fold and sulcus. Furthermore, the microornament of Pentagonospirifer n. gen. consists of capillae with pustules on them (only on ribs) whereas the micro-ornament of gen.

Pentagonospirifer n. gen. is distinguished externally from Lamarckispirifer

Gatinaud, 1949

from the lower Famennian of South China as revised by

Ma and Day (2007)

, by its inflated shell, its high and subogival tongue, the larger number of ribs on flanks and fold and in sulcus, and by the absence of a median furrow on fold that is generally present in Lamarckispirifer. Moreover, Pentagonospirifer n. gen. differs by the presence of a strong apical callus developed on the delthyrial plate and by its unsupported ctenophoridium.

Occurrence.-This species occurs in the lower Famennian Ertych Regional Stage that is correlated with the Cyrtospirifer orbelianus brachiopod Zone of

Abrahamyan (1957)

and the Cyrtiopsis orbelianus-Cyrtiopsis armenicus brachiopod Zone of

Rzhonsnitskaya and Mamedov (2000)

(see Fig.

3

). commissures; highest in the posterior third of the valve, then decreasing progressively towards anterior margin; umbo strongly inflated, large and prominent; beak straight to suberect; interarea apsacline, triangular

Table 8 .

 8 Measurements

		W	L	T	Ws	dL	L/W	T/W	Ws/W	W/dL
	Number of individuals	33	33	33	33	33	33	33	33	33
	Mean value	32.46	29.3	24.3	22.1	0.9	0.9	0.75	0.68	0.31
	Standard deviation	3.087	2.8113	2.97	2.3882	0.05	0.05	0.07	0.0688	0.034
	Standard error±	±0.5374 ±0.489	±0.5161	±0.4157	±0.231	±0.0087	±0.0118	±0.012	±0.0059
	Min	26.1	22.8	17	9.2	17.5	0.81	0.64	0.55	0.25
	Max	36.7	34.1	29.2	16.5	27.4	1.04	0.92	0.87	0.38

in mm and ratios of Pentagonospirifer abrahamyanae n. gen., n. sp. Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

  Uchtospirifer subarchiaci[START_REF] Martelli | Il Devoniano superiore dello Schensi (Cina)[END_REF] sensu Afanasjeva inAlekseeva et al. (2018b) (not Plicapustula subarchiaci[START_REF] Martelli | Il Devoniano superiore dello Schensi (Cina)[END_REF], seeMa and Day 2007) is also included in the new genus. Moreover, it most likely belongs to the same phylogenetic linage of A. arakelyani n.gen., n. sp. as both species display strong intraspecific similarities.

	Diagnosis.-Shell medium-to large-sized, ventribiconvex, subpentagonal, with mucronate to
	rounded cardinal extremities; ventral interarea moderately high, triangular, apsacline; delthyrium
	wide; fold low; sulcus narow; ribs numerous, low, rounded; increasing by bifurcation in sulcus and
	on fold; micro-ornament of closely spaced growth lines, sometimes thickened as growth varices;
	dental plates robust, extrasinal posteriorly then becoming subsinal or intrasinal anteriorly; delthyrial
	plate short; ctenophoridium composed of numerous vertical lamellae and supported by a strong
	callosity.

;

Grechishnikova in Alekseeva et al., 2018 b)

did not reveal specimens that could be assigned to Pentagonospirifer abrahamyanae n. gen. n. sp. The main difference of the latter species from other early Famennian cyrtospiriferids of Armenia is the presence of delthyrial thickening that is formed by a development of strong apical callus on delthyrial plate, around dental plates and floor of ventral valve. It is worth noting that one of the striking features of P. abrahamyanae n. gen. n. sp. is its suitability for brachiopod encrusters, since until now, among the spiriferides described in Armenia, encrusters are observed only in the specimens of this species.

Genus Angustisulcispirifer new genus

Type species.-Angustisulcispirifer arakelyani n. gen., n. sp., Frasnian, Central Armenia.

Other included species.-As the morphological characters of Cyrtospirifer (C.) kursaensis

Sidjachenko, 1962 and C. (C.)

limatus Solkina in

Sidjachenko (1962)

from the Famennian of Central Kara-Tau (Kazakhstan) fit well with the diagnosis of the new genus, the latter are assigned to it, though the type of pseudodeltidium as well as the micro-ornament of both species are undocumented.

  from the upper Givetian?-lower Frasnian strata of Russia and possibly upper Givetian of Poland, based on its ventribiconvex profile, subpentagonal shell with flanks closely ornamented by low, flattened ribs and high ventral interarea, but the former displays wide hinge line (vs. short hinge line for Uchtospirifer), mucronate cardinal extremities (vs. rounded ones for Uchtospirifer), narrow sulcus and fold (vs. moderately wide ones for Uchtospirifer).Additionally, the new genus has ribs in sulcus and on fold that are not transformed into capillae, flattening or disappearing as it is observed in Uchtospirifer representatives. Internally, Angustisulcispirifer n. gen. differs by its supported ctenophoridium.Angustisulcispirifer n. gen. is separable from Plicapustula Ma and Day, 2007, known from the lower Famennian of South China and North America, by its more rounded and longitudinally elongated shell outline, low fold, narrow sulcus and very low tongue. Furthermore, Angustisulcispirifer n. gen. resembles some representatives of Wenjukovispirifer Oleneva, 2016 in terms of size, general shape and outline, but the new genus differs externally by its larger size as well as poorly developed fold and sulcus. It is worth noting that only a little is known about length; central apical cavity moderately filled in by callus that is rounded in shape, lateral apical cavities large and moderately filled by callus; delthyrial plate short; ctenophoridium composed of numerous vertical lamellae and supported by a strong callosity; hinge plates divided.

	Angustisulcispirifer n. gen. differs by its more robust dental plates, rudimentary delthyrial plate and
	supported ctenophoridium.

The new genus differs externally from the upper-uppermost Famennian genus Dichospirifer

Brice, 1971

, as revised by

Mottequin and Brice (2019)

, by its larger size, shell shape, wide hinge line and narrow but conspicuous sulcus and fold. Moreover, the former bear simple and flattened ribs on flanks, while the latter has bifurcating ribs, exceptionally trifurcating or increasing by intercalation on flanks

(Mottequin and Brice 2019)

. Additionally, Angustisulcispirifer n. gen. differs by its supported ctenophoridium, whereas Dichospirifer representatives possess an unsupported ctenophoridium bilobed posteriorly.

Table 9 .

 9 Measurements in mm and ratios of Angustisulcispirifer arakelyani n. gen., n. sp. Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus, dL-length of the dorsal valve.

		W	L	T	Ws	dL	L/W	T/W	Ws/W	W/dL
	Number of individuals	50	50	50	50	50	50	50	50	50
	Mean value	29	26.91	22.44	20.6	8.8	0.92	0.67	0.3	0.71
	Standard deviation	7.131	7.0832	21.55	5.7482	3.1153	0.0495	0.049	0.051	0.04
	Standard error±	±1.0084 ±1.002	±1.1783	±0.8129	±0.4406	±0.007	±0.007	±0.0071	±0.006
	Min	18.4	15.9	11.5	12	3	0.77	0.55	0.15	0.58
	Max	51.2	49.5	37.2	38.1	19.8	0.98	0.76	0.39	0.77

  Murchison sensu[START_REF] Nalivkin | Brakhiopody verkhnego i srednego devona i nizhnego karbona Severo-Vostochnogo Kazakhstana: Tsentral'nyi Nauchno-Issledovatel[END_REF] also from Central Kara-Tau may be considered for assignment to this genus, but it is impossible to assign it with certainty as its internal morphology and microornament are unknown. Spirifer murchisonianus de Koninck sensuReed (1922: pl. 10, figs. 3-12; Tornatospirifer n. gen. mainly differs externally from CyrtiopsisGrabau, 1923 sensu Ma and Day (1999) from the lower Famennian of China, by its high ventral interarea, its pseudodeltidium composed of several distinct plates and by its clearly defined sulcus contrary to those with rounded lateral boundaries occurring in Cyrtiopsis representatives. The essential internal difference between both genera is the presence of a well-developed delthyrial plate in Tornatospirifer n. gen., whereas it is absent in Cyrtiopsis.Tornatospirifer n. gen. shares several external and internal similarities with the genus Uchtospirifer Ljashenko, 1957 sensuSokiran (2006). More particularly, both genera display a brachythyrid shell, subpentagonal in outline and ornamented with closely spaced and flattened ribs, an apsacline and triangular ventral interarea, as well as intrasinal and divergent dental plates. Cyrtiopsis senceliae armenicaAbrahamyan; Mottequin and Brice 2019, p. 56.

	2018b Cyrtiopsis caucasia Grechishnikova; Afanasjeva in Alekseeva et al., p. 1005, pl. 29, figs. 5-
	6; text-fig. 101.
	pl. 11, figs. 1-7) from the Famennian (excluding the lowermost and uppermost Famennian according to Sartenaer, 1970) of Pamir (Tajikistan) probably belongs to the new genus. Although 2019 Neotype.-After extensive search at the Geological Museum of Yerevan, none of the syntypes
	Reed (1922) did not illustrate serial sections, he mentioned the presence of dental plates and dorsal illustrated by Abrahamyan (1974: pl. 21, fig. 1, pl. 22, fig. 4) was recovered from Abrahamyan's
	median septum (he apparently observed the development of a callus supporting the ctenophoridium) collection; they are therefore considered as lost. Consequently, one of the recently collected
	that fit well with the diagnosis of Tornatospirifer n. gen. specimens from the Ertych Regional Stage (lower Famennian) of the Shamamidzor section (type
	locality) (Lanjanist village, Ararat province, West Central Armenia; Fig. 1) is hereby designated as
	the neotype (IGSNASRAGM 3980/PS 30488) and figured in Plate 13.1-13.8.
	Tornatospirifer n. gen. is distinguished externally from Ghorispirifer Mottequin and Brice,
	Etymology.-Tornatus, a, um (Latin): rounded; spirifer is a common suffix used in the spiriferide 2019, known from the upper-uppermost Famennian of Afghanistan and Iran by its high ventral
	genera. The name refers to the rounded subpentagonal shell shape. interarea and by its micro-ornament, which is composed of capillae and numerous pustules only on
	ribs Ghorispirifer has capillae with pustules both on ribs and in interspaces. The most substantial

Type species.-Cyrtiopsis senceliae armenica

Abrahamyan, 1974, lower Famennian, Armenia.

Other species.-Cyrtiopsis caucasia

Grechishnikova, 1986

is considered here as a junior synonym of the type species of Tornatospirifer n. gen. as we observed all superficial features that were supposed to separate the latter from Abrahamyan's species. Cyrtiopsis senceliae Sartenaer sensu

Sidjachenko (1962)

and Cyrtospirifer (Cyrtospirifer) helenae

Sidjachenko, 1962

from Central and southeastern Kara-Tau (Kazakhstan) are allocated to this genus although the pseudodeltidium and micro-ornament of the latter are unknown due to poor preservation. Spirifer (Cyrtospirifer) archiaci Diagnosis.-Shell medium-sized, ventribiconvex, rounded subpentagonal, brachythyrid with obtuse or rounded cardinal extremities (though the latter are worn in most of the studied specimens); ventral interarea triangular, high, apsacline; delthyrium relatively wide, covered by a pseudodeltidium formed by several distinct plates; fold and sulcus wide, well-defined; ribs numerous, simple on flanks, increasing by bifurcation in sulcus and on fold; micro-ornament of closely spaced growth lines, cappilae occurring only on ribs and numerous pustules developed only capillae; dental plates long, strong, intrasinal; delthyrial plate well-developed; ctenophoridium supported by an apical callosity; hinge plates divided. Occurrence.-Lower Famennian of Armenia and Nakhichevan, probably the Famennian of Pamir (Tajikistan) and likely the Famennian of Central and southeastern Kara-Tau (Kazakhstan).

Remarks.-Tornatospirifer n. gen. is placed within the Subfamily Cyrtiopsinae due to its brachythyrid shell and obtuse or rounded cardinal extremities.

However, Tornatospirifer n. gen. is differing by its more globular shell, the type of pseudodeltidium (formed by several distinct plates), the development of ribs in sulcus and on fold that are not transforming into capillae, flattening or disappearing as it is observed in Uchtospirifer representatives. Internally Tornatospirifer n. gen. is distinguished by its supported ctenophoridium whereas the latter is unsupported in Uchtospirifer.

Tornatospirifer n. gen. differs from the lower Famennian genus Pseudocyrtiopsis

Ma and Day, 1999

, by its general shape and outline, bifurcating ribs in sulcus and on fold as well as lack of capillae that are developed in the interspaces of Pseudocyrtiopsis representatives. Although, it is also worthwhile to stress that these genera have quite similar internal morphology (e.g. strong, divergent dental plates, a well-developed delthyrial plate and a supported ctenophoridium). difference lies in the ventral internal morphology. In Tornatospirifer n. gen. the dental plates are connected by a well-developed delthyrial plate which is absent in Ghorispirifer.

Table 10 .

 10 Measurements in mm and ratios of Tornatospirifer armenicus

		W	L	T	Ws	dL	L/W	T/W	Ws/W	W/dL
	Number of individuals	42	39	39	41	40	39	39	41	39
	Mean value	29.97	26.57	22.44	12.54	20.7	0.89	0.74	0.42	0.69
	Standard deviation	3.0263	3.0372	2.846	1.7461	1.46	0.0545	0.064	0.0466	0.0504
	Standard error±	±0.467	±0.486	±0.4557	±0.2727	±0.231	±0.0087	±0.0103	±0.0073	±0.0081
	Min	21.2	19.4	16.1	9.2	18.2	0.76	0.56	0.35	0.59
	Max	33.7	31.3	27.5	16.5	24	0.99	0.91	0.52	0.82

  Cyrtospiriferinae gen. et sp. 2, Sinospirifer sp. 1, Sinospirifer sp. 2, Angustisulcispirifer arakelyani n. gen., n. sp.), while the Interval 4 bears six spiriferides (Cyrtospirifer? sp., Cyrtospirifer pseudoasiaticus n. sp., Pseudocyrtiopsis areniensis n. sp., Aramazdospirifer orbelianus(Abich, 1858), Pentagonaspirifer abrahamyanae n. gen., n. sp. and Tornatospirifer armenicus

  noted the presence of this genus in the upper Givetian of Poland, while several Ripidiorhynchus representatives were reported from the lower Frasnian of Main Devonian Field (northwestern Russia), lower Famennian of East European Platform (Eastern Europe) (see referencesin Sokiran, 2006) as well as from the Frasnian of Nakhichevan(Pakhnevich 2018 in Alekseeva et al., 2018a). Therefore, it is judicious to assume that firstly occurred in the upper Givetian of Poland, this genus was later expanded to the north-western region of platform due to the early Frasnian transgression and later to the south-east, migrating towards the northern margin of Gonwana; it thus colonized the Frasnian carbonate platform of SAB and persisted until the lower Famennian strata within the Armenian Djravank section.

This is the first time that the genus Porthmorhynchus is recognized (although doubtfully)

  4. The taxonomic reassessment of the newly collected brachiopods led us to erect a number of new species and genera, but also to update previous assignments based on newly observed features that were poorly illustrated or unknown until now. Most notably, Spinatrypa ertichensisAbrahamyan, 1974 is revised and re-assigned to Atryparia (Costatrypa)[START_REF] Copper | New Siluro-Devonian atrypoid brachiopods[END_REF] mainly based on its frilly ornamentation. CyrtospiriferNalivkin in Fredericks, 1924 is one of the main components of Frasnian-Famennian assemblages in Armenia; it appears to include four species, of which Cyrtospirifer pseudoasiaticus n. sp., one of the most abundant species in the lower Famennian sequence, is new to science. The genus Pseudocyrtiopsis is transferred from the Subfamily Cyrtiopsinae to the Subfamily Cyrtospiriferinae based on some features (high ventral interarea, wide hinge line and mucronate cardinal extremities)

that are observed in Pseudocyrtiopsis areniensis n. sp. Four new genera are erected:

Aramazdospirifer Pentagonaspirifer, Angustisulcispirifer and Tornatospirifer.

  -Shell medium-sized, wider than long, sharply dorsibiconvex, transversally elliptic in outline; widest in the anterior third of the valve; highest slightly posteriorly to the front; anterior margin slightly emarginate to straight; anterior commissure strongly uniplicate.

	delimited by bounding ribs, flat-bottomed at the front; tongue high, wide, subtrapezoidal in 1957) rather than Brice's species as they clearly have a different shell shape, strongly emarginate
	outline, perpendicular to the commissural plane or bent dorsally. anterior commissure and markedly inflated ventral umbo.
	Dorsal valve markedly inflated, regularly curved in both the posterior and lateral profile
	views, with convex flanks sloping moderately to steeply towards the lateral commissures;
	highest more posteriorly to the front, then decreasing progressively towards the posterior margin;
	fold moderately high, inconspicuously originating at some distance from the umbo, round-
	topped at the front.
	F o Ornamentation of coarse, angular ribs, originating at beaks and becoming fainter towards lateral cardinal extremities; 9-10 ribs on the flanks, 3 ribs in sulcus, 3-4 ribs on fold; ribs wider F o
		r r
	than interspaces.	R R
	e Ventral valve interior (Fig. 6) with thin, relatively long dental plates converging e
	v i ventrally; teeth stout; central apical cavity wide. Dorsal valve interior (Fig. 6) with long and high v i
	e w e septum, extending up to ca. 20% of the valve's length; septalium narrow, relatively long, moderately deep, covered anteriorly by stout connectivum bearing a median crest; hinge plates w
	long, connected; crural bases nearly horizontal.	O n O n
			l l
	y Material examined.-Twenty-two articulated specimens and four ventral valves; eight y
	articulated specimens and two ventral valves come from the Ertych section, five articulated
	Ventral valve regularly convex in posterior and lateral profile views, with flanks slopping specimens and two ventral valves from the Djravank section and nine articulated specimens from
	gently towards the lateral commissures; highest in the posterior third of the valve, then the Noravank section.
	decreasing gently towards the anterior margin; umbo slightly inflated; beak and foramen
	unobserved; sulcus wide, moderately deep, starting at midlength or slightly posteriorly, well-Remarks.-Jafarian (2000) reported S. charakensis from the upper Famennian of Iran, but his
	illustrated specimens appears to be closer to Sinotectirostrum delicatacostatum (Abrahamyan,

  thatSartenaer (2001) mentioned that the septalium of Porthmorhynchus representatives is covered by a connectivum, which was not observed in our ground specimen. However, it should be stressed that this delicate structure is not always preserved. Additional material is needed for reaching a more confident identification.

	moderately high, wide, subtrapezoidal in outline, perpendicular to commissural plane or slightly
	bent dorsally.
	Dorsal valve inflated, strongly curved in posterior and lateral profile views, with convex
	flanks sloping steeply towards the lateral commissures; highest slightly posteriorly to the front,
	then progressively decreasing towards the posterior margin; fold starting at some distances from
	the umbo, low, wide, well-defined, becoming relatively higher anteriorly. Subfamily Ripidiorhynchinae Savage, 1996
	Ornamentation of coarse, angular, low to moderately high ribs, radiating at beaks,
	F o becoming fainter towards the lateral cardinal extremities; ribs in sulcus and on fold slightly wider than those present on the flanks; 2 ribs in sulcus, 3 ribs on fold, 6-7 ribs on flanks, parietal ribs o F Genus Gesoriacorostrum Sartenaer, 2003
		r r
	R unobserved; ribs wider than interspaces. R Type species.-Atrypa boloniensis d'Orbigny, 1850.
	e Ventral valve interior (Fig. 7) with relatively long and robust dental plates converging e
	v i ventrally; teeth massive; central apical cavity wide; lateral apical cavities poorly infilled by v i Gesoriacorostrum? sp.
	e w callosities. Dorsal valve interior with relatively high and long septum (Fig. 7(1-2.7)); septalium wide, relatively deep; connectivum not observed; hinge plates divided; dental sockets large; e w Figures 8-9
	crural bases stout.	O n O n 14.9 mm in width, 13.4 mm in length and 10 mm in l l
	thickness), dorsibiconvex, widest and highest more anteriorly to midlength, rounded y Material examined.-Two partly exfoliated articulated specimens. y
	subpentagonal in outline; anterior margin slightly rounded; anterior commissure uniplicate.
	Ventral valve regularly convex in posterior and lateral profile views, with flanks slopping Remarks.-Porthmorhynchus Sartenaer is mainly known from middle-upper Frasnian strata of
	gently towards the lateral commissures; highest in the posterior third of the valve; umbo inflated, the Boulonnais region in Northern France (Brice in Brice and Meats, 1972; Sartenaer, 2001). Our
	prominent; beak and foramen unobserved (due to poor preservation); sulcus relatively wide, material is doubtfully assigned to this genus as the development of its fold and sulcus
	shallow to moderately deep, originating at about midlength, flat-bottomed at the front; tongue (originating far from the beaks), as well as the orientation of its dental plates (converging
	ventrally) are in contradiction with the diagnosis of the genus. Furthermore, it is worth nothing

  .-Shell small-sized (ca.19 mm in width, 16.5 mm in length, 8.3 mm in thickness),

	bottomed at front; tongue low, wide, subtrapezoidal in outline, not perpendicular to commissural
	plane.
	Dorsal valve highest at midlength or slightly anteriorly to it, then decreasing regularly
	towards anterior margin; fold only developed close to anterior margin, very low, wide, round-
	topped at front.
	Ornamentation of up to 13 low, flattened, simple ribs on each flank originating at beaks
	and becoming progressively fainter towards posterolateral margins; in sulcus and on fold, 7-8
	o F ribs, infrequently increasing by bifurcation; ribs wider than interspaces on the entire shell.
	r
	R
	e
	v i
	e
	w
	O n
	l
	y
	dorsibiconvex, wider than long, widest and highest at about midlength, transversally elliptic in
	outline; anterior margin slightly rounded; anterior commissure uniplicate.
	Ventral valve regularly convex in posterior and lateral profile views, with flanks slopping
	gently towards lateral commissures; umbo small; beak and foramen unobserved (due to poor
	preservation); sulcus only perceptible close to anterior margin, very shallow, wide, round-

  with its type species Sharovaella mirabilis. Although the external and internal morphology of our material is a reminiscent of S. mirabilis in terms of size, general shape, well-developed fold and sulcus, short dental plates, covered, narrow septalium and low septum, this limited material is tentatively assigned to Sharovaella as it lacks strong ribs running from the umbo on flanks and in sulcus and on fold, contrary to what it is observed in Pakhnevich's material. Moreover,

	high, perpendicular to the commissural plane or slightly bent dorsally, high, subtrapezoidal in
	outline.
	Dorsal valve strongly inflated with markedly convex flanks sloping moderately to
	steeply towards the lateral commissures; highest at midlength or more anteriorly to it, then
	decreasing progressively towards the posterior margin; umbo flattened, not prominent; beak
	small, overhanging the hinge line; fold high, well-delimited, wide, originating at midlength or
	slightly posteriorly, then becoming higher anteriorly, round-topped at front.
	F o Ornamentation of 3-4 coarse, strong ribs on flanks originating at midlength by intercalations, becoming shorter and weaker towards the posterolateral margins; in sulcus and on fold, 1-2 ribs F o
	r r
	R originating near the umbo or more anteriorly to it; ribs wider than interspaces, having rounded R
	e apices and being triangular in cross section; growth lamellae densely crowded, relatively e
	v i prominent (2-3 lamellae per 1 mm) and penetrated by irregularly arranged punctae situated near v i
	e w e the umbo on ventral valve. Ventral valve interior (Fig. 15) with thin intrasinal and slightly divergent dental plates, central and lateral apical cavities poorly filled in by callosities. w
	mm in width, 11 mm in length and 8.4 mm in thickness), wider than long, strongly dorsibiconvex, rounded subpentagonal in outline, widest at midlength, O n l Dorsal valve interior with low but long septum (Figs. 12.2, 12.4, 13(1.15)); septalium O n covered and narrow; hinge plates short; crural bases stout. l
	highest at midlength or slightly anteriorly; anterior margin slightly emarginate; anterior y y
	commissure uniplicate. Material examined.-Three articulated specimens.
	Ventral valve gently inflated in posterior and lateral profile views, with slightly convex
	flanks sloping gently towards the lateral commissures; highest at midlength, then progressively Remarks.-Pakhnevich (2012) examined several specimens collected by Grechishnikova from
	decreasing towards the anterior margin; umbo prominent, somewhat curved; beak small, straight different sections of Armenia and Nakhichevan identified as Eoparaphorhynchus triaequalis
	to inclined; foramen unobserved; sulcus well-defined by bounding ribs, wide, deep, originating (Gosselet, 1877); he noticed that this material differs from Gosselet's species by the presence of
	from midlength or slightly posteriorly, flat to round-bottomed at the front; tongue wider than punctae on the shell walls. Consequently, he erected the new monospecific genus Sharovaella

Table 4

 4 Occurrence and age.-This species is only found in the South-Armenian Block. More particularly, according to

	1952 Athyris globularis Phill. Arakelyan, p. 32-33, 40, 41.
	1957 Athyris globularis; Abrahamyan, p. 9, table 2.
	1964 Athyris globularis; Arakelyan, p. 75, 82-83, 94.
	1973 Athyris globularis; Abrahamyan et al., p. 218.
	1974 Athyris globularis; Abrahamyan, p. 9.
	2000 Athyris ex gr. globularis; Rzhonsnitskaya and Mamedov, p. 330.
	F o Holotype.-An almost complete articulated specimen (IGSNASRAGM XX; Fig. 16.24-28) from
	r
	R the lower Famennian orbelianus Zone of Abrahamyan (1957) Ertych section which is correlated
	e with the Ertych horizon (Fig. 2); Ertych section (6 km southeast from Areni, Vayots Dzor
	Province, central Armenia).	v i
		e
	w Diagnosis.-Shell medium-sized (up to 24 mm in width, 22.5 mm in length, 21.2 mm in
	thickness), aequibiconvex, relatively aequidimensional, rounded pentagonal in outline; anterior O n l margin straight to poorly emarginate; anterior commissure strongly uniplicate; fold and sulcus
	y very shallow, wide at the front, more developed anteriorly; tongue moderately high to high,
	subtrapezoidal to semioval in outline; micro-ornament of imbricate, densely crowded growth
	lines projecting anteriorly and anterolaterally as flattened, radially-aligned solid spines; dental
	plates thin, relatively long and arched supporting cyrtomatodont teeth, lateral apical cavities
	strongly filled in by callosities; dorsal interior with cardinal plate pierced apically by a dorsal
	foramen; inner hinge plates conjunct, weakly concave ventrally to nearly flat depending on
	specimens; outer hinge plates flat; myophragm very short.

  .-Juveniles display a rectimarginate to slightly uniplicate anterior commissure, semielliptic tongue and sharp lateral commissures. Although not visible on juveniles, sulcus and fold develop with age. The beak inclination angle does not change with age, as juveniles also have a suberect to erect beak. The maximum height of the dorsal valve is near the umbo in juveniles then moves towards the anterior margin. The shell growth follows a linear model, as this is more

	F o
	r
	R
	e
	v i
	e
	w
	O n
	l
	y

  as a biostratigraphically important species for the lower Famennian orbelianus Zone. Moreover, until now it was confused with Spirifera globularis Phillips, 1836, a poorly known species from the Viséan of Bolland (Yorkshire, UK) which is currently assigned to the genus Composita (see[START_REF] Brunton | A check list of brachiopods from Treak Cliff, Derbyshire, with reference to other Dinantian (Lower Carboniferous) localities[END_REF]. This species is assigned herein to CrinisarinaCooper and Dutro, 1982 rather than to Cleiothyridina markedly higher tongue and more developed sulcus and fold. The most significant internal difference is the presence of strong callosities in lateral apical cavities of C. angelicoides, whereas the lateral apical cavities of C. pseudoglobularis sp. nov. are moderately filled in.

	F o
	r
	R
	e
	Buckman, 1906 because of its markedly inflated shell, rounded pentagonal outline, strongly v i
	uniplicate anterior commissure and highly inflated umbones e	.
	C. pseudoglobularis sp. nov. is very close to C. stainbrooki Mottequin, 2008, known w
	from the lower Famennian of southern Belgium and the USA (Nevada, New Mexico) (see references in Mottequin, 2008); however, C. pseudoglobularis differs externally by its more O n
		l
	inflated shell, aequibiconvex lateral profile and narrower tongue and internally, by the presence y
	of thick lens of prismatic calcite in the middle part of the ventral valve and long myophragm.
	C. pseudoglobularis sp. nov. displays strong similarities to Crinisarina angelicoides
	(Merriam, 1940), a species known from the lower Famennian to ?middle Famennian of Nevada,
	southern Belgium, Cracow area and Holy Cross Mountains (Poland) and doubtfully reported
	from Alberta (Canada) and the Harz Mountains (Germany) (see references in Baranov, Sokiran
	and Blodgett, 2016); however C. pseudoglobularis is nearly as wide as long and it thus displays a
	different outline. Moreover, C. angelicoides has a sharply parasulcate anterior commissure, a

  C. pseudoglobularis sp. nov. differs externally from C. shashishanensis[START_REF] Mottequin | Late middle Frasnian to early Famennian (Late Devonian) strophomenid, orthotetid and athyridid brachiopods from southern Belgium[END_REF] from the middle Famennian of South Tianshan (China), by its larger and thicker shell, poorly emarginate to straight anterior margin, less developed fold and sulcus and relatively lower subtrapezoidal to semioval tongue. Internally, the new species is distinguished by the presence of a thick lens of prismatic calcite developed in the middle part of the ventral valve, well-developed umbonal callus and the absence of a stout dorsal myophragm. . pseudoglobularis sp. nov. seems to be similar to C. reticulatiformis Modzalevskaya and Pushkin, 2012 from the middle Famennian of Belarus, but the latter differs by its always longer than wide shell and by its more solid spines covering the shell. The most significant difference lies in the ventral internal morphology. In C. reticulatiformis, the umbonal callus is divided into two parts by the median groove and lateral apical cavities are strongly filled in, whereas the lateral apical cavities of our material are only moderately filled in and the umbonal callus is not divided, instead it is supported by a thick lens of prismatic calcite developed in the middle part of the valve.

	F o
	r
	R
	e
	v i
	e
	w
	O n
	l
	y
	C. pseudoglobularis sp. nov. may be distinguished from C. ligularis Modzalevskaya and
	Pushkin, 2012, a middle Famennian species from Belarus, by its larger shell with width
	exceeding the length and more or less aequidimensional lateral profile. It is difficult to compare
	the internal morphologies of both as Modzalevskaya and Pushkin (2012) did not illustrate serial
	sections of their material.

C. pseudoglobularis sp. nov. differs superficially from C. neutra

Modzalevskaya and Pushkin, 2012

occurring in the lower Famennian of Belarus by its shell size, general outline and poorly developed sulcus. Furthermore, our material is also distinguished internally by its relatively stout dental plates, the presence of a thick lens of prismatic calcite developed in the middle part of the ventral valve, a well-developed umbonal callus, a comparably long dorsal myophragm.

C

  Crinisarina pseudoglobularis sp. nov. and Sartenaerus baitalensis show similar slope for their Width/Length ratios, Crinisarina pseudoglobularis sp. nov. exhibit longer length relative to its width than Sartenaerus baitalensis. In the same way, while Sartenaerus charakensis and Sartenaerus baitalensis show similar slope for their Width/Length ratios, Sartenaerus baitalensis exhibit longer length relative to its width than Sartenaerus charakensis.The scatter plot of Width/Thickness ratios and linear regression lines for all the four species are presented Figure17. The shell growth for each species follows a linear model, as this is more particularly reflected by the significant coefficient of correlation (Fig.17; p<0.001*** or p<0.01**). For the Width/Thickness ratios, if equal adjusted means (between-groups effect) in the four species taxa can be rejected at p<0.005 (p=8.34E-15***), equality of slopes can be Finally, the scatter plot of Width/Width of Sulcus ratios and linear regression lines for all the four species are presented Figure 18. The shell growth for each species follows a linear Sartenaerus baitalensis and Greira transcaucasica show similar Width//Width of Sulcus ratios with Sartenaerus baitalensis rather represented by larger individuals while Greira transcaucasica is represented by smaller individuals. Interestingly, Sartanearus charakensis seems to be represented as an intermediate form with rather similar Width//Width of Sulcus ratios. Moreover, while Crinisarina pseudoglobularis sp. nov. and Sartenaerus baitalensis show similar slope for their Width/Width of Sulcus ratios, Sartenaerus baitalensis exhibit more important Width of Sulcus relative to its Width than Crinisarina pseudoglobularis sp. nov.

	F o F o
	r r
	R R
	e e
	v i v i
	e e
	w w
	O n O n
	l l
	y y
	; p<0.001***). For the
	Width/Length ratios, if equal adjusted means (between-groups effect) in the four species can be
	rejected at p<0.005 (p=1.06E-20***), equality of slopes cannot be rejected (p=0.9735 NS). In model, as this is more particularly reflected by the significant coefficient of correlation (Fig. 18;
	addition, it is interesting to underline that Sartenaerus baitalensis, and Greira transcaucasica p<0.001***). For the Width/Width of Sulcus ratios, if equal adjusted means (between-groups
	effect) in the three taxa can be rejected at p<0.005 (p=3.59E-15***), equality of slopes cannot
	be rejected (p=0.6946NS). As for the Width/Length ratios, it is interesting to underline that

show similar Length/Width ratios with Sartenaerus baitalensis rather represented by larger individuals while Greira transcaucasica is represented by smaller individuals. Moreover, while rejected also (p=0.00905***). Moreover, if equal adjusted means (between-groups effect) in Sartenaerus baitalensis and Greira transcaucasica can be rejected at p<0.005 (p=1.18E-08***), equality of slopes cannot be rejected (p=0.7051 NS). In the same way, if equal adjusted means (between-groups effect) in Sartenaerus baitalensis and Sartenaerus charakensis can be rejected at p<0.005 (p=0.00028***), equality of slopes cannot be rejected (p=0.9728 NS). Sartenaerus baitalensis exhibit more important thickness relative to its width than Sartenaerus charakensis and than Greira transcaucasica.

  )). The other species assigned to this genus P. elburzensis is known from the upper Frasnian of the Alborz Mts (northern Iran). Thus, the doubtful presence of this genus in the lower Famennian orbelianus Zone of Armenia is significant, although it requires further study to confirm its presence. indeed in the entire northern margin of Gondwana, even if it is not excluded that Crinisarina representatives are present in the Famennian of North Africa (Algeria and Morocco), where taxonomical studies have been mostly dedicated to the rhynchonellides, productidines and spiriferides, whereas the other elements of the brachiopod faunas received scant attention (see referencesin Mottequin et al., 2015). Alike other species of Crinisarina (see discussion in[START_REF] Mottequin | Late middle Frasnian to early Famennian (Late Devonian) strophomenid, orthotetid and athyridid brachiopods from southern Belgium[END_REF], it is likely that C. pseudoglobularis sp. nov. had a preference for soft substrates, made of argillaceous sediments on which it was attached with a thin pedicle. This corresponds well to our own observations, as this species was found mainly in shaly intervals.

	F o
	r
	R
	e
	v i
	e
	w
	O n
	l
	y
	Greira transcaucasica is one of the oldest punctate rhynchonellide species and, as it is
	only known from the SAB, this may represent an interesting case of endemicity.

The single athyridide species recognized (Crinisarina pseudoglobularis sp. nov.) represents also the first ever report of genus Crinisarina in the South-Armenian Block and

  Crinisarina pseudoglobularis sp. nov.) and, thus, to report the first occurrence of the genus Crinisarina in the SAB and the entire north Gondwanan realm. The paleobiogeographic distribution of the rhynchonellides and athyridides within the lower Famennian of Armenia suggests that the brachiopod communities thriving on the shallow water carbonate platform of the SAB contained some apparently endemic species (G. transcaucasica and C. pseudoglobularis sp. nov.), but also species that were in common with other parts of the Gondwanan northern margin extending eastwards to Afghanistan and Pamir.

	F o o F o F o F o F o F o F o F o F o the late Paleozoic basement: Boulder, Colorado, Geological Society of America, Special Paper, v. 364, p. 263-280. Ziegler, W., Sandberg, C.A., 1990, The Late Devonian standard conodont zonation: Courier new athyridide species (F Forschungsinstitut Senckenberg, v. 121, p. 1-115.
	r r r r r r r r r r
	R R R R R R R R R R
	e e e e e e e e e e
	v i v i v i v i v i v i v i v i v i v i
	e e e e e e e e e e
	w w w w w w w w w w
	O n O n O n O n O n O n O n O n O n O n
	l l l l l l l l l l
	y y y y y y y y y y

  from the lower Famennian 'Cyrtospirifer'

	section), almost complete specimen in ventral, dorsal, lateral, posterior and anterior views. 16-
	20. IGSNASRAGM 3903/PS 3009 (Djravank section), partly exfoliated specimen in ventral,
	dorsal, lateral, posterior and anterior views. 21-25. IGSNASRAGM 3904/PS 3010 (Noravank
	section), articulated specimen in ventral, dorsal, lateral, posterior and anterior views. 26-30.
	IGSNASRAGM 3905/PS 3011 (Noravank section), articulated specimen in ventral, dorsal,
	lateral, posterior and anterior views. Scale bars: 5 mm (1-10), 10 mm (11-30).
	F o
	r
	R
	e
	v i
	e
	w
	O n
	l
	y
	orbelianus Zone in Armenia. 1-5. IGSNASRAGM 3900/PS 3006 (Ertych section), almost
	complete juvenile specimen in ventral, dorsal, lateral, posterior, and anterior views. 6-10.
	IGSNASRAGM 3901/PS 3007 (Ertych section), partly exfoliated juvenile specimen in ventral,
	dorsal, lateral, posterior and anterior views. 11-15. IGSNASRAGM 3902/PS 3008 (Djravank

  Greira transcaucasicaErlanger, 1993, and Crinisarina pseudoglobularis sp. nov. Abbreviations:

	F o
	r
	R
	e
	v i
	e
	w
	O n
	l
	y
	Figure 18. Scatter diagram exhibiting the relation between shell width (in mm) and width of
	sulcus (in mm) of Sartenaerus baitalensis (Reed, 1922), Sartenaerus charakensis (Brice, 1967),

, Greira transcaucasica

Erlanger, 1993, and

Crinisarina pseudoglobularis sp. nov. Abbreviations: n, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value. n, number of specimens measured; y=ax+b, linear model; r, coefficient of correlation; p***, significant probability value.

Table 4 .

 4 Measurements in mm and ratios of Crinisarina pseudoglobularis sp. nov.

		W	L	T	Ws	L/W	T/W	Ws/W
	Number of
	individuals	34	34	33	32	34	33	32
	Mean value
		21.97	19.1	17.24	11.56	0.87	0.78	0.52
	Standard deviation
		3.2136	3.2879	3.0715	2.5165	0.0776	0.1152	0.0663
	Standard error±
		±0.5511 ±0.5639 ±0.5347 ±0.4449 ±0.0133 ±0.0201 ±0.0117
	Min
		15.1	12.9	10.7	7	0.69	0.65	0.4
	Max
		26	25.4	23.8	15.8	0.99	1.01	0.61

Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

Table 1 .

 1 Measurements in mm and ratios of Sartenaerus baitalensis(Reed, 1922).

	Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width
	of the sulcus.

Table 2 .

 2 Measurements in mm and ratios of Sartenaerus charakensis(Brice, 1967).

	Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width
	of the sulcus.

Table 3 .

 3 Measurements in mm and ratios of Greira transcaucasicaErlanger, 1993

		W	L	T	Ws	L/W	T/W	Ws/W
	Number of
	individuals	43	43	40	27	43	40	27
	Mean value
		18.36	18.03	14.69	6.64	0.98	0.79	0.35
	Standard deviation
		2.7128	2.5439	3.1965	2.1134	0.0641	0.0959	0.0938
	Standard error±
		±0.4137 ±0.3879 ±0.5054 ±0.4067 ±0.0098 ±0.0152 ±0.0181
	Min
		12.2	11	7.2	1	0.87	0.55	0.06
	Max
		24	22.5	21.2	9.7	1.16	0.99	0.46

Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus.

Table 4 .

 4 Measurements in mm and ratios of Crinisarina pseudoglobularis sp. nov. cyrtospiriféride et une espèce biostratigraphique importante du Famennien inférieur (Dévonien supérieur) d'Arménie Le nouveau genre Aramazdospirifer (Cyrtospiriferidae) est ici érigé, afin d'inclure Spirifer orbelianus Abich, 1858 du Famennien inférieur d'Arménie centrale comme son espèce type et résoudre ainsi des discussions de longue date sur l'affinité générique de cette espèce. La microornementation et la structure interne de celle-ci sont étudiées et documentées pour la première fois, sur la base de matériel récemment récolté dans trois coupes différentes au sein de l'horizon Ertych. En outre, un néotype est sélectionné pour cette espèce décrite initialement par Abich étant donné que le matériel type est perdu. Aramazdospirifer orbelianus (Abich, 1858) est une espèce biostratigraphiquement importante du Famennien inférieur du Petit Caucase. Cette espèce semble être restreinte au bloc Sud-Arménien ; des rapports la mentionnant à l'extérieur du domaine gondwanien sont discutés et écartés.

Abbreviations: W-width of the shell, L-length of the shell, T-thickness of the shell, Ws-width of the sulcus. brachiopode

  in honor of the Orbelian family, one of the strongest dynasties in medieval Armenia, characterized by a long history of political influence documented in inscriptions throughout the provinces of Vayots Dzor and Syunik. Abich found this species in the lower Famennian sequence exposed at Noravank although he did not explicitly mention this locality. Abich (1858, p. 524) indicated that 'Sp. Orbelianus ist bis jetzt nur in dem Baranco des Erhebungsthales von Gyneschik [= Gnishik], in den Schichten h and k Profils pag.

Plate 9

Cambridge University PressJournal of Paleontology

Acknowledgements /Remerciements

Acknowledgments V. Serobyan is grateful to the French Embassy in Armenia and the MOBLILEX International Mobility Grant Programme of the University of Lille for funding his studies in France. T. Danelian and A. Grigoryan acknowledge the financial support of the Erasmus + International Credit Mobility Programme for their staff mobility in 2018 and 2019, respectively. C. Crônier acknowledges the financial support of the Lille Institute on Environmental Sciences (IRePSE).

Fieldwork was also facilitated by the logistic support of the Institute of Geological Sciences (Armenian Academy of Sciences). The authors thank the Région Hauts-de-France, and the Ministère de l'Enseignement Supérieur et de la Recherche (CPER Climibio), and the European Fund for Regional Economic Development for their financial support. Sylvie Régnier (UMR Evo-Evo-Paleo, ULille) is gratefully acknowledged for the high-quality SEM pictures obtained on specimens deposited at IGNASRAGM. Acknowledgments The Ph.D. studies of V. Serobyan in France are funded by the French Embassy in Yerevan and the MOBLILEX International Mobility Grant Programme of the University of Lille. T. Danelian and A. Grigoryan are grateful to the Erasmus Programme for funding their staff mobility in 2018 and 2019, respectively. Fieldwork was also facilitated by the logistic support of the Institute of Geological Sciences (Armenian Academy of Sciences). The authors thank the Région Hauts-de-

France, and the Ministère de l'Enseignement Supérieur et de la Recherche (CPER Climibio), and the European Fund for Regional Economic Development for their financial support. Sylvie Régnier (UMR Evo-Evo-Paleo, ULille) and Julien Cillis (RBINS, Brussels) are gratefully acknowledged for the high-quality SEM pictures obtained on specimens deposited at IGNASRAGM and at the RBINS, respectively. Daria Bezgodova is thanked for kindly providing information about Abich's collection. Constructive remarks by Jed Day, Elena Sokiran and an anonymous reviewer improved the initial manuscript. The authors are also grateful to E. Sokiran for her advice on literature related to brachiopod genera described from the ex-USSR.

I am grateful to the French Embassy in Armenia for providing me a 15 month grant over three years, which allowed the launch of this co-tutorial PhD. I am also grateful to the University of Lille for providing me a 4 month MOBLILEX International Mobility Grant and to the Erasmus + International Credit Mobility Programme for funding the last year of my PhD studies in France. I would like to thank the Institute of Geological Sciences (Armenian Academy of Sciences) for its my deep gratitude to Dr. B.

Chapter 5

Brachiopod diversity, stratigraphy and paleobiogeography

Although, the Frasnian assemblage includes species of five brachiopod orders, one more than the lower Famennian, while comparing these two assemblages, it becomes evident that the lower Famennian contains more diversified brachiopod fauna then the Frasnian at the subfamily, genus and species levels. The brachiopod orders constituting these assemblages differ in diversity from one assemblage to another one. Interestingly, the spiriferids were predominant in both assemblages, whereas the rhynchonellides, being relatively scarce in the Frasnian, flourished within the lower Famennian as is the case of productides.

abrahamyanae n. gen., n. sp. (IGSNASRAGM 3928/PS 3034;Pl. 9.11,9.15,9.18) are colonial organisms referred to Hederella Hall, 1883 that is a still enigmatic encrusting metazoan known from the Silurian to the Permian and were most common in the Devonian period. It is similar to cyclostome bryozoans, but it is not a bryozoan because of its branching patterns, lack of an astogenetic gradient, skeletal microstructure, and wide range in tube diameters [START_REF] Wilson | Pseudobryozoans" and the problem of encruster diversity in the Paleozoic: PaleoBios[END_REF]. Possibly, it is some lophophorate-grade animal of uncertain affinity. Additionally, it should be emphasized that the Upper Devonian brachiopods from the Lesser Caucasus were never investigated with respect to encrustation patterns and this is the very first report documenting their presence on the lower Famennian spiriferids of Armenia.

. well-constrained age of the occurrence of S. baitalensis in the Lesser Caucasus (the species occurs only in the Cyrtospirifer orbelianus Zone) this is not the case for the occurrence of S. baitalensis in Pamir (Reed, 1922). Finally, the apparent absence of both species in other parts of the northern Gondwanan margin, especially in Morocco, may be due to the presence of deeper (cephalopodbearing) facies for this interval and therefore it may reflect a paleoenvironmental rather than paleobiogeographical signal.

Conclusions

Plate 11

Angustisulcispirifer arakelyani n. gen., n. sp. from the Frasnian Cyrtospirifer subarchiaci-Cyphoterorhynchus arpaensis Zone of Rzhonsnitskaya and Mamedov (2000), Armenia. The arrows indicate the anterior margin.

(1-3). IGSNASRAGM 3975/PS 3081 (Ertych section), details of the micro-ornament from the lateral oblique view (1-2) and close to the anterior margin (3) showing only the growth lines that are still visible in more internal layers of the shell.

(4). IGSNASRAGM 3976/PS 3082, close-up of the ornament displaying the faint ribs in the sulcus.

Scale bars: 1 mm (1), 0.5 mm ( 2), 400 μm (3-4).

Plate 13

Tornatospirifer armenicus (Abrahamyan, 1974) from the lower Famennian Cyrtospirifer orbelianus Zone of Abrahamyan (1957), Central Armenia.

(1-8). IGSNASRAGM 3981/PS 3087 (neotype, Shamamidzor section), partly exfoliated specimen in ventral, dorsal, lateral, posterior, posterodorsal and anterior views (1-6), and close-up of the micro-ornament (capillae with pustules) on dorsal valve (7-8).