Roque Aguado

Miguel Company

Luis O'dogherty

José Sandoval

Mathieu Martinez

Ujaen Es

New insights into the Barremian-lower Aptian calcareous nannofossils of the Mediterranean Tethys: Chronostratigraphic and paleobiogeographic implications

Keywords: Taxonomy, Biometry, Biogeography, Bio-chronostratigraphy, Barremian-Aptian boundary, Betic Cordillera

A detailed study of calcareous nannofossil assemblages from twelve uppermost lower Barremian-lower Aptian sections in the Subbetic domain of the Betic Cordillera was performed. Seven new nannofossil species (Crucibiscutum bastetanum, Crucibiscutum gracile, Chiastozygus lamprostauros, Cyclagelosphaera platyaspis, Lithraphidites aichmoides, Lithraphidites pugio, and Rhagodiscus sicutclipeus) are described, one species is emended (Lithraphidites magnus) and the taxonomic concept of the marker species Hayesites irregularis is discussed and clarified. The detailed stratigraphic ranges of the new species, together with those of other relevant taxa, are determined and correlated to standard ammonite biostratigraphy. Age estimates of biostratigraphically relevant calcareous nannofossil biohorizons are calculated using astrochronologically tuned cyclostratigraphic data. Five new calcareous nannofossil subzones are proposed J o u r n a l P r e -p r o o f Journal Pre-proof which enhance upper Barremian biostratigraphic resolution at a regional scale and are directly correlated with respect to the standard Tethyan ammonite zonation. Two of the new species described here are used as biostratigraphic markers for the newly proposed subzones. The duration of each subzone is provided through astrochronological calibration. This study allows the refinement of the calcareous nannofossil zonation for the Mediterranean-Atlantic province of the Tethyan domain. The implications of these new results are discussed regarding the extant definition and use of the Barremian/Aptian boundary. The morpho-evolutionary trends of selected nannofossil groups are reviewed in relation to the latest Barremian-Aptian paleogeographic changes, showing these were a prominent factor controlling calcareous nannoplankton evolution and biogeographical distribution in the west European-Atlantic region.

Introduction

The Barremian Stage (~125.98 to ~121.40 Ma; [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF] records a particular interval marked by notable environmental and biotic changes. These include two episodes of accelerated environmental change (e.g., [START_REF] Föllmi | Early Cretaceous life, climate and anoxia[END_REF]: the Mid-Barremian Event (MBE; [START_REF] Coccioni | The Mid-Barremian Event (MBE): the prelude to the OAE1a[END_REF][START_REF] Sprovieri | Orbital tuning of a lower Cretaceous composite record (Maiolica Formation, central Italy)[END_REF][START_REF] Yilmaz | The first record of the "Mid-Barremian" Oceanic Anoxic Event and the Late Hauterivian platform drowning of the Bilecik platform, Sakarya Zone, western Turkey[END_REF][START_REF] Huck | Carbon-isotope stratigraphy of Early Cretaceous (Urgonian) shoal-water deposits: Diachronous changes in carbonate-platform production in the north-western Tethys[END_REF]Aguado et al., 2014a) and the Taxy Episode (TE; [START_REF] Masse | La matière organique dans la série du stratotype historique de l'Aptien inférieur dans la région de Cassis-La Bédoule (SE France)[END_REF]Moullade et al., 1998a;[START_REF] Föllmi | Early Cretaceous life, climate and anoxia[END_REF][START_REF] Wissler | Chemostratigraphic correlation of Barremian and lower Aptian ammonite zones and magnetic reversals[END_REF][START_REF] Godet | Evolution of marine stable J o u r n a l P r e -p r o o f Journal Pre-proof carbon-isotope record during the early Cretaceous: A focus on late Hauterivian and Barremian in the Tethyan realm[END_REF][START_REF] Stein | Progressive palaeoenvironmental change during the Late Barremian-Early Aptian as prelude to Oceanic Anoxic Event 1a: Evidence from the Gorgo a Cerbara section (Umbria-Marche basin, central Italy)[END_REF][START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF]. Both episodes were linked to carboncycle perturbations locally related to enhanced preservation of organic-rich marine sediments.

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The Barremian successions of argillaceous limestones and marlstones of the Subbetic Domain in the Betic Cordillera are well dated by ammonites (e.g., [START_REF] Company | Secuencias deposicionales en el Barremiense-Aptiense inferior de la Sierra del Corque (Cordillera Bética): consideraciones paleogeográficas[END_REF][START_REF] Company | Secuencias deposicionales en el Barremiense-Aptiense inferior de la Sierra del Corque (Cordillera Bética): consideraciones paleogeográficas[END_REF][START_REF] Company | Ammonite biostratigraphy of the uppermost Hauterivian in the Betic Cordillera (SE Spain)[END_REF][START_REF] Aguado | Biostratigraphic analysis of the pelagic Barremian/Aptian in the Betic Cordillera (southern Spain). Preliminary data[END_REF][START_REF] Aguado | Biostratigraphic events at the Barremian/Aptian boundary in the Betic Cordillera (southern Spain)[END_REF], and proved to contain abundant and moderately to well-preserved calcareous nannofossil assemblages (e.g., [START_REF] Aguado | Biostratigraphic events at the Barremian/Aptian boundary in the Betic Cordillera (southern Spain)[END_REF]Aguado et al., , 2014a)). Some of these successions were also studied for C-isotope stratigraphy, both MBE and TE were identified in them (e.g., Aguado et al., 2014a;[START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF], and they have been recently calibrated by astrochronology [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF]. These successions represent good candidates to improve Tethyan calcareous nannofossil biostratigraphy by providing adequate chronostratigraphical and geochronological frameworks to tie all the biostratigraphic events.

The aim of this paper is to improve the resolution of the Barremian calcareous nannofossil biozonation for the Mediterranean so it can be used as an alternative to ammonite zones. The stratigraphic range of the calcareous nannofossil species with biostratigraphic potential, together with that of other relevant taxa, will be directly correlated to standard ammonite biostratigraphy and to the geochronologic scale.

Finally, as the Barremian/Aptian boundary is included within the interval studied, it will be discussed in the light of new findings.

Geological setting

All sections studied belong to the Subbetic Domain (Fig. 1), a complex tectonostratigraphic unit that paleogeographically corresponds to the pelagic areas of the southern passive margin of the Iberian Plate during the Alpine tectonic cycle (Triassic to early Miocene). During the Jurassic and Early Cretaceous this region underwent extensional tectonics associated with the seafloor spreading of the North Atlantic in a J o u r n a l P r e -p r o o f Journal Pre-proof transform continental margin setting [START_REF] Vera | Evolution of the Southern Iberian Continental Margin[END_REF][START_REF] Vera | Cordillera Bética y Baleares[END_REF]Martín-Chivelet et al., 2019). A paleolatitude of ~26-28º N (Fig. 2) has been inferred for the Barremian-early Aptian position of the Subbetic Domain (e.g., [START_REF] Barron | Paleogeography, 180 million years ago to the present[END_REF][START_REF] Stampfli | Europe from the Variscan to the Alpine cycles[END_REF][START_REF] Cao | Improving global paleogeography since the late Paleozoic using paleobiology[END_REF][START_REF] Barrier | Paleotectonic Reconstruction of the Central Tethyan Realm[END_REF], being located near the boundary between the aridtropical and humid-temperate climatic belts (e.g., [START_REF] Masse | Early Aptian (114-111 Ma)[END_REF] http://www.scotese.com/ecretcli.htm; Fig. 2).

Except for X.Cp 2 section (see Chapter 3), all sections studied belong to the widely extended Lower Cretaceous Carretero Formation (Figs. 3,4). Roughly, the lithologic succession of this formation (e.g., [START_REF] De Gea | Bioestratigrafía y eventos del Cretácico Inferior en las Zonas Externas de la Cordillera Bética[END_REF]) consists of a rhythmic alternation of yellowish to gray argillaceous limestone beds (5-90 cm thick) and gray marlstone interbeds (3-760 cm thick). The lime fraction is partially made up of calcareous nannofossil remains and carbonate particles of micritic size (micarbs) which probably originated from the adjacent platforms. Clay minerals are, by far, the main components of the detrital fraction (e.g., [START_REF] Aguado | Análisis estratigráfico integrado del Hauteriviense terminal-Barremiense inferior de la sección de Arroyo Gilico (Murcia)[END_REF]. Overlying the Carretero Formation, some sections include parts of the Argos, Fardes, or Carbonero formations (Figs. 3,4; see also Supplementary Material 1 (SM1) for details on lithostratigraphy and biostratigraphy).

Material and methods

A total of 575 samples, spread across 12 sections were studied. These include, from West to East (Fig. 1):

-Caprés (A in Fig. 1. Section X.Cp 2 ; 38.233078°N, 1.134206°W; 16 samples; Fig. 4).

-Arroyo de Gilico (B in Fig. 1. Section X.V 1 ; 38.159931°N, 1.678208°W; 77 samples; Fig. 3).

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Journal Pre-proof -Barranco de Cavila (C in Fig. 1. Section X.Kv: 38.051514°N, 1.885713°W; 57 samples; Fig. 3. Section X.Kv 2 : 38.052469°N, 1.888964°W; 222 samples; Fig. 3).

-Río Argos (D in Fig. 1. Section X.Ag6: 38.051514°N, 1.885713°W; 15 samples; Fig. 4).

-Rambla Seca (E in Fig. 1. Section RA03: 37.794622°N, 2.030255°W; 32 samples; Fig. 3).

-Cerro Trompeta y Cortijo del Hielo (F in Fig. 1. Section X.CT: 37.866290°N, 2.575907°W; 8 samples; Fig. 4. Section X.HA: 37.851783°N, 2.588921°W; 29 samples; Fig. 4).

-Barranco de las Azadillas (G in Fig. 1. Section X.Z: 37.779300°N, 2.708924°W; 12 samples; Fig. 4).

-La Frontera (H in Fig. 1. Section X.F: 37.591233°N, 3.602561°W; 56 samples; Fig. 4. Section X.F1: 37.593226°N, 3.603832°W; 39 samples; Fig. 4).

-La Coronilla (I in Fig. 1. Section X.CO 2 : 37.546093°N, 3.937009°W; 13 samples; Fig.

4).

Although sections X.Cp 2 , RA03, X.CT, X.HA, X.F, X.F1 and X.CO 2 have been studied previously (see SM1), new smear-slides were prepared and studied for all samples. Samples from X.V 1 , X.Kv, X.Kv 2 , X.Ag6 and X.Z sections (370) are new. The number of samples studied in each section and their respective positions are stated in figures 3, 4, and in Supplementary Material 2 (SM2). The sampling intervals were highly variable (Figs. 3 and4), from 6-7 cm (e.g., sections X.V 1 and X.Kv 2 ) to several meters (e.g., lower part of X.F section). Except for samples from the RA03 section and those from the uppermost Barremian to lower Aptian parts of the X.F and X.F1 sections, the remainder of them are directly correlated to ammonite zones/subzones [START_REF] Aguado | Nannofósiles del Cretácico de la Cordillera Bética[END_REF] J o u r n a l P r e -p r o o f Journal Pre-proof [START_REF] Aguado | Biostratigraphic analysis of the pelagic Barremian/Aptian in the Betic Cordillera (southern Spain). Preliminary data[END_REF][START_REF] Aguado | Biostratigraphic events at the Barremian/Aptian boundary in the Betic Cordillera (southern Spain)[END_REF][START_REF] Aguado | Bioestratigrafía de alta precisión del Barremiense mediterráneo mediante nanofósiles calcáreos[END_REF]Company et al., 1995, and this paper). In the present work, the standard ammonite zonation for the Mediterranean Province [START_REF] Reboulet | Report on the 6th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the Kilian Group[END_REF] is followed, and used as a reference to calibrate the calcareous nannofossil bioevents. In the absence of magnetostratigraphical data, the base of the Deshayesites oglanlensis ammonite Zone (AZ) is used here to determine the base of the Aptian [START_REF] Reboulet | Report on the 4th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the "Kilian Group[END_REF][START_REF] Reboulet | Report on the 6th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the Kilian Group[END_REF].

Simple permanent smear slides [START_REF] Bown | Techniques[END_REF] were mounted with coverslips for routine biostratigraphic analysis and examined for nannofossil content using a polarizing light microscope Olympus BHSP at 1200 × magnification. At least a complete longitudinal traverse (= 200 fields of view; surface area of one field = 2.37 × 10 -2 mm 2 ) was studied, but in some slides several (up to 4) longitudinal traverses were studied. Special care was taken to prepare the smear slides as uniformly as possible, so that particle density on the slide surface was kept between 30-50% [START_REF] Baccelle | Diagrammi per la stima visiva della composizione percentuale nelle rocce sedimentarie[END_REF]. To determine the stratigraphic position of the horizon from which the wide-canal nannoconids are more abundant than narrow-canal nannoconids (wc>nc Event) in some sections (RA03, X.F, X.HA, X.Kv and X.Kv 2 ), nannoconids were counted in 50 fields of view on samples selected according to their biostratigraphic position. The percentages of wide canal (including Nannoconus bucheri, N. circularis, N. truittii; N. sp. cf. N. truittii, N. vocontiensis and N. wassallii) and narrow canal (including Nannoconus bermudezii and N. steinmannii) forms were calculated (see SM2). The used taxonomic framework is based on [START_REF] Perch-Nielsen | Mesozoic calcareous nannofossils[END_REF], [START_REF] Bown | Calcareous Nannofossil Biostratigraphy[END_REF][START_REF] Bown | Early to mid-Cretaceous calcareous nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise[END_REF], [START_REF] Aguado | Biostratigraphic events at the Barremian/Aptian boundary in the Betic Cordillera (southern Spain)[END_REF]Aguado et al. ( , 2014b, c), c), and the nannotax website (http://www.mikrotax.org/Nannotax3/index.php?dir=Mesozoic).

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Journal Pre-proof Preservation in the assemblages was evaluated in each sample (see SM2) based on the visual criteria established by [START_REF] Roth | Calcareous nannoplankton: Leg 14 of the Deep Sea Drilling Project[END_REF] and [START_REF] Roth | Jurassic and Lower Cretaceous calcareous nannofossils in the western north Atlantic (Site 534): biostratigraphy, preservation, and some observations on biogeography and paleoceanography[END_REF]. Limestone beds were avoided for sampling, as they contain impoverished (poorly to moderately preserved) assemblages with moderate to heavily overgrown taxa. Overall abundance per sample was estimated by counting the total number of nannofossils in 20 random fields of view.

Photomicrographs of calcareous nannofossils were acquired with an Olympus Camedia C5050 camera attached to the Olympus BHSP microscope, using cross-polarized light (XPL). A wide variability of size was observed for some taxa recorded throughout the studied interval. To test whether size of specific taxa fluctuates throughout the studied interval, specimens of Lithraphidites spp. (120), Hayesites irregularis group (140) and Flabellites oblongus (120) were photographed and measured. In addition, some specimens (6-22) of the new species described were also photographed and measured.

The results are documented in the SM2. Measurements were taken using ImageJ software, with an accuracy of ± 0.03 μm. Regarding precision, in a set of 10 repetitive measurements of 10 specimens, the error was lower than ±0.14 μm with a 95% confidence level. The lengths (L) and widths (W) of Lithraphidites spp., H. irregularis gr. and F. oblongus specimens were later used to test whether these three groups consist of several taxa.

To test the supposed multimodality in the populations of the measured taxa, mixture analyses were applied to the whole data sets, (i.e., all specimens of each group pooled together) using the free PAST v4.05 software package [START_REF] Hammer | PAST: paleontological statistics software package for education and data analysis[END_REF]. This statistical analysis is a maximum-likelihood method for estimating the descriptive J o u r n a l P r e -p r o o f Journal Pre-proof parameters (mean, standard deviation and proportion) of two or more distinct distributions, based on an initially pooled univariate sample [START_REF] Hammer | Paleontological Data Analysis[END_REF]. The minimum values of the Akaike Information Criterion (AIC, [START_REF] Akaike | A new look at the statistical model identification[END_REF] helped to identify the groups obtained by mixture analysis with the lowest overfitting [START_REF] Hammer | PAST: paleontological statistics software package for education and data analysis[END_REF]. The number of bins for histograms in mixture analyses follows the Sturges' rule (k = (log 2 n) + 1), where k is the number of bins and n the number of observations).

Results

Nannofossil abundance and preservation

Calcareous nannofossil abundance usually fluctuates between > 5 and 30 specimens per field of view (SFOV), with only discrete samples showing abundances below 5 SFOV, while 22 samples were barren (see SM2). Nannofossil assemblages are rich and moderately to well preserved, showing slight to moderate overgrowth except for those from the organic-rich beds of X.Ag6 and X.Z sections, which showed moderate to strong etching (see SM2).

Mixture analyses

Fluctuations observed in length (L) and width (W) in the pool of the measured specimens of Lithraphidites spp. (Fig. 5A-D) suggest that several species can be differentiated. The results of a mixture analysis performed on the W values (Fig. 5E) reveal three different-sized groups. The first group corresponds to L. carniolensis (Fig. 5A), while the second and third group correspond to L. aichmoides (Fig. 5B; Chapter 6) and to the L. pugio/L. magnus plexus respectively (Fig. 5C,D). The same statistical analysis was applied to the length (L) of all specimens with W greater than 4.5 μm (L.

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Journal Pre-proof pugio/L. magnus plexus). The frequency histogram (Fig. 5G) reveals the existence of two different-sized groups, which represent the new species L. pugio and L. magnus (Fig. 5C, D; Chapter 6). Figure 5H shows the descriptive parameters resulting from the mixture analysis performed on W in the whole data set and on L in those specimens having a W greater than 5 μm. However, total length (L) proved not to be an outright criterion to separate the latter two species, being more effective distinguishing both taxa using the L/W ratio (Fig. 6; see also Chapter 6).

Hayesites irregularis is an important marker species in the Tethyan Realm (e.g., [START_REF] Thierstein | Lower Cretaceous calcareous nannoplankton biostratigraphy[END_REF][START_REF] Perch-Nielsen | Mesozoic calcareous nannofossils[END_REF][START_REF] Bralower | An integrated Cretaceous microfossil biostratigraphy[END_REF]. Its taxonomic clarification can increase the biostratigraphic precision of stratigraphic correlations.

Variations observed in the length (L) and width (W) of the specimens measured in this study (Fig. 7A,B) suggest the presence of two morphotypes in the H. irregularis group (gr.). This was corroborated by the results of a mixture analysis on the L/W ratio of the complete pool of measurements (Fig. 7C). Forms with a nearly circular outline, (L/W smaller or equal to 1.12), being younger in time, were assigned to H. irregularis sensu stricto (s.str.). Specimens having a more elongated outline (L/W>1.12) and poorly defined elements, being slightly older, were assigned to H. irregularis morphotype E (H. irregularis E; Chapter 6).

Mixture analyses performed on size measurements (L and W) of specimens of Flabellites oblongus sensu lato (s.l.) spread across the uppermost lower Barremianlower Aptian of the study sections (see SM2 and Fig. 8) provided non-conclusive results. These showed similar AIC values for unimodal/bimodal solutions suggesting a J o u r n a l P r e -p r o o f Journal Pre-proof rather continuous increase in size through the complete data pool (Fig. 8) thereby hindering a clear separation of different populations (see Chapter 6).

Sequence of nannofossil bioevents

One hundred and four taxa were identified through the complete interval studied, including 7 new species (see SM2 and Chapter 6). The following sequence of bioevents (from bottom to top) has been observed:

-Presence of Braarudosphaera hockwoldensis (Holcodiscus fallax ammonite subzone [ASz]).

-Lowest occurrence (LO) of Flabellites oblongus (Holcodiscus caillaudianus ASz).

-LO of Lithraphidites aichmoides (Moutoniceras moutonianum ammonite zone [AZ]).

-Successive LOs of Phosterolithus prossii, Crucibiscutum gracile and Lithraphidites pugio (Gassendiceras alpinum ASz).

-LO of Rhagodiscus sicutclipeus (lowermost part of the Gerhardtia sartousiana ASz).

-Successive LOs of Chiastozygus lamprostauros, Micrantholithus stellatus and Rhagodiscus gallagheri (Gerhardtia provincialis ASz).

-LO of Hayesites irregularis E, highest occurrences (HOs) of Lithraphidites pugio and A summary of the main bioevents recorded and their stratigraphic context is shown in Figure 9.

Discussion

Biostratigraphic remarks

Although most of the taxa shown in Figure 9 [START_REF] Rutledge | New names for old: taxonomic clarification of some Early Cretaceous nannofossil marker-species[END_REF].

Other bioevents, such as the FOs of Flabellites oblongus and Hayesites irregularis have been used as biostratigraphic markers (e.g., [START_REF] Thierstein | Lower Cretaceous calcareous nannoplankton biostratigraphy[END_REF][START_REF] Thierstein | Mesozoic calcareous nannoplankton biostratigraphy of marine sediments[END_REF]Bralower et al.1995), but they were never adequately correlated to ammonite biostratigraphy. The LO of F. oblongus was recently identified in the lower part of the Moutoniceras moutonianum AZ (Aguado et al., 2014a;[START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF]. Here we report the LO of F. oblongus from the Holcodiscus caillaudianus ASz in the X.Kv and X.V 1 sections. This species is very rare and shows a spotty record throughout the H. caillaudianus ASz and lowermost part of the M. moutonianum AZ. Its consistent record (Figs. 3,9) correlates with the level where Aguado et al. (2014a) and [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF] reported the LO of this species. Hayesites irregularis E is rather rare near its LO and is more abundant from the upper part of the Hemihoplites feraudianus ASz. The LO of H. irregularis s.str. (Chapter 4.3 and Fig. 9) was not recorded until the mid part of the Imerites giraudi AZ (Figs. 3,4;SM2).

Finally, a small group of taxa have shown fairly continuous and consistent records.

These include Lithraphidites pugio, whose LO was already successfully used in regional correlation (as L. sp. cf. L. magnus) by [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF], Micrantholithus stellatus, and the distinctive Crucibiscutum bastetanum (Fig. 9 andSM2). In addition, the stratigraphic horizon from which the proportion of wide-canal nannoconids outnumber the narrow-canal nannoconids (wc>nc Event,Figs. 3,4,9; sections X.HA, X.Kv, X.Kv 2 and SM2), has also proven to be a good correlation event. In some sections (RA03, X.F, X.F1), this horizon is masked by a stratigraphic break surface (see

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Figs. 3, 4, andSM2). The onset of the 'nannoconid decline' event (e.g., [START_REF] Erba | Integrated stratigraphy of the Cismon APTICORE (Southern Alps, Italy): a "reference section" for the Barremian-Aptian interval at low latitudes[END_REF][START_REF] Erba | The response of calcareous nannoplankton to Oceanic Anoxic Events: The Italian pelagic record[END_REF][START_REF] Channell | Early Cretaceous magnetic stratigraphy in the APTICORE drill core and adjacent outcrop at Cismon (Southern Alps, Italy), and correlation to the proposed Barremian-Aptian boundary stratotype[END_REF][START_REF] Erba | Calcareous nannofossils and Mesozoic oceanic anoxic events[END_REF][START_REF] Tremolada | Late Barremian to early Aptian calcareous nannofossil paleoceanography and paleoecology from the Ocean Drilling Program Hole 641C (Galicia Margin)[END_REF] was not determined in this study.

Proposed biozones

Here we document a detailed zonation of the upper Barremian-lower Aptian interval of the Mediterranean area. The zonation uses the scheme of [START_REF] Bralower | An integrated Cretaceous microfossil biostratigraphy[END_REF] by adding new subzones as digits. The proposed subzones are useful on a regional scale (e.g., [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF], but they could be applied to the Mediterranean-Atlantic area, as some of the marker species were also recorded from outside of the Betic Cordillera (chapters 5.4, 6).

NC5E1 Subzone. (New subzone)

Base: LO of Flabellites oblongus. Calibrated here to 124.72 Ma, slightly earlier than in [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF]. This bioevent also corresponds to the base of the NC5E Subzone [START_REF] Bralower | An integrated Cretaceous microfossil biostratigraphy[END_REF]. Currently, the boundary between the Barremian and Aptian Stages is provisionally located at the base of the CM0r magnetochron, and the Gorgo a Cerbara section is its possible Global Stratotype Section and Point [START_REF] Erba | The Aptian Stage[END_REF]. This designation was made based on the supposed proximity of the lower boundary of CM0r to the LO of deshayesitid ammonites (=base of the Aptian used by ammonite specialists; e.g., [START_REF] Reboulet | Report on the 6th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the Kilian Group[END_REF]. However, magnetostratigraphic record is very poorly preserved in hemipelagic sections where ammonite zonations are established and, to date, no direct calibration of magnetic polarity and ammonite zones is so far available for the upper Barremian-lowermost Aptian interval.

The LO of Hayesites irregularis has been reported in Gorgo a Cerbara from ~6 m below the base of CM0r [START_REF] Patruno | The Barremian and Aptian stepwise development of the 'Oceanic Anoxic Event 1a' (OAE 1a) crisis: Integrated benthic and planktic high-resolution palaeoecology along the Gorgo a Cerbara stratotype section (Umbria-Marche Basin, Italy)[END_REF]. New findings (Martinez et al., 2020, and present paper) indicate that the LO of H. irregularis gr. occurs in the lower part of the Hemihoplites feraudianus ASz (see chapters 4.3 and 5.1), below that reported by [START_REF] Aguado | Biostratigraphic events at the Barremian/Aptian boundary in the Betic Cordillera (southern Spain)[END_REF]. This is consistent with the stratigraphy of Gorgo a Cerbara proposed by [START_REF] Frau | The Aptian GSSP candidate at Gorgo a Cerbara (Central Italy): an alternative interpretation of the bio-, litho-and chemostratigraphic markers[END_REF], and indicates that the LO of H. irregularis is far below the base of the Aptian as defined by the first appearance of deshayesitids.

The wc>nc Event (e.g., [START_REF] Erba | Integrated stratigraphy of the Cismon APTICORE (Southern Alps, Italy): a "reference section" for the Barremian-Aptian interval at low latitudes[END_REF][START_REF] Larson | Onset of the Mid-Cretaceous greenhouse in the Barremian-Aptian: Igneous events and the biological, sedimentary, and geochemical responses[END_REF][START_REF] Channell | Early Cretaceous magnetic stratigraphy in the APTICORE drill core and adjacent outcrop at Cismon (Southern Alps, Italy), and correlation to the proposed Barremian-Aptian boundary stratotype[END_REF][START_REF] Bellanca | Palaeoceanographic significance of the Tethyan 'Livello Selli ' (Early Aptian)from the Hybla Formation, northwestern Sicily: biostratigraphy and highresolution chemostratigraphic records[END_REF][START_REF] Tremolada | Late Barremian to early Aptian calcareous nannofossil paleoceanography and paleoecology from the Ocean Drilling Program Hole 641C (Galicia Margin)[END_REF][START_REF] Erba | The response of calcareous nannoplankton to Oceanic Anoxic Events: The Italian pelagic record[END_REF] was recorded in the Gorgo a Cerbara section within CM0r [START_REF] Channell | Early Cretaceous magnetic stratigraphy in the APTICORE drill core and adjacent outcrop at Cismon (Southern Alps, Italy), and correlation to the proposed Barremian-Aptian boundary stratotype[END_REF][START_REF] Patruno | The Barremian and Aptian stepwise development of the 'Oceanic Anoxic Event 1a' (OAE 1a) crisis: Integrated benthic and planktic high-resolution palaeoecology along the Gorgo a Cerbara stratotype section (Umbria-Marche Basin, Italy)[END_REF]. This horizon has been here correlated to the lower part of the Martelites sarasini AZ (Figs. 3, J o u r n a l P r e -p r o o f requires time-consuming analyses to be determined, and probably is not a good alternative as a primary marker to be used in the definition of the base of the Aptian, but it could be used as a secondary indicator at least in the Tethyan Realm.

The HO of the new coccolith species Crucibiscutum bastetanum follows the wc>nc Event and slightly predates the onset of the C-isotope Intra-Sarasini Negative Excursion (ISNE) linked to the Taxy Episode [START_REF] Föllmi | Early Cretaceous life, climate and anoxia[END_REF][START_REF] Frau | Stable carbon-isotope chemostratigraphy versus ammonite biostratigraphy: data from around the Barremian/Aptian boundary (Lower Cretaceous)[END_REF][START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF].

According to the chronology of [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF], this bioevent predates the Barremian/Aptian boundary by 0.57 myr, being a moderately good approximation to it.

However, this new species has been identified only in the Subbetic Domain as yet.

The LOs of Nannoconus truittii and Rhagodiscus angustus (upper part of Deshayesites oglanlensis-lower part of Deshayesites forbesi AZs) do not provide reliable events because they are masked by the presence of specimens with transitional morphologies (see chapters 5.1 and 6). No other reliable calcareous nannofossil event has been recorded from the Betic Cordillera, until the 'nannoconid crisis', which has been correlated to the upper part of the D. forbesi AZ [START_REF] Aguado | Aptian bioeventsan integrated biostratigraphic analysis of the Almadich Formation, Inner Prebetic Domain, SE Spain[END_REF][START_REF] Moreno-Bedmar | Biostratigraphic characterization by means of ammonoids of the lower Aptian Oceanic Anoxic Event (OAE 1a) in the eastern Iberian Chain (Maestrat Basin, eastern Spain)[END_REF][START_REF] Föllmi | Early Cretaceous life, climate and anoxia[END_REF].

The C-isotope ISNE, has been identified in several sections within the mid-upper part of the Martelites sarasini AZ [START_REF] Kuhnt | Carbon isotope stratigraphy of the lower Aptian historical stratotype at Cassis-La Bédoule (SE France)[END_REF]Moullade et al., 1998a, b;[START_REF] Godet | Evolution of marine stable J o u r n a l P r e -p r o o f Journal Pre-proof carbon-isotope record during the early Cretaceous: A focus on late Hauterivian and Barremian in the Tethyan realm[END_REF][START_REF] Frau | Stable carbon-isotope chemostratigraphy versus ammonite biostratigraphy: data from around the Barremian/Aptian boundary (Lower Cretaceous)[END_REF][START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF]. Its top is close to the base of the Aptian as defined by ammonite biostratigraphy. In sections from SE France and Spain (see also [START_REF] Sanchez-Hernandez | The influence of regional factors in the expression of oceanic anoxic event 1a (OAE1a) in the semi-restricted Organyà Basin, south-central Pyrenees, Spain[END_REF], the ISNE is made of two spikes with lower J o u r n a l P r e -p r o o f Journal Pre-proof C-isotope values separated by a short excursion with slightly higher values (Fig. 10). In the Gorgo a Cerbara section the ISNE consists of only one spike in the δ 13 C curve, which is located at the top of CM0r and correlates with the change from the 'Maiolica' to the 'Marne a Fucoidi' formations (e.g., [START_REF] Godet | Evolution of marine stable J o u r n a l P r e -p r o o f Journal Pre-proof carbon-isotope record during the early Cretaceous: A focus on late Hauterivian and Barremian in the Tethyan realm[END_REF][START_REF] Stein | Progressive palaeoenvironmental change during the Late Barremian-Early Aptian as prelude to Oceanic Anoxic Event 1a: Evidence from the Gorgo a Cerbara section (Umbria-Marche basin, central Italy)[END_REF]Frau et al., 2018).

Figure 10 summarizes the findings of the current study around the Barremian-Aptian interval and correlates the X.Kv 2 section and some relevant French and Italian sections by using bio-and chemostratigraphy. Given the proximity of the ISNE (especially its top) to the base of D. oglanlensis AZ, we think this negative excursion of the δ 13 C carb is an alternative for defining the base of the Aptian.

Barremian-Aptian calcareous nannofossil morpho-evolutionary trends and paleobiogeography

Although the driving factors for size changes of calcareous nannofossils have been discussed in the last decades, both for living assemblages and for fossil species, these remain still unclear. In living assemblages, some link was found within coccolith morphology and environmental factors such as sea-water temperature and salinity (e.g., [START_REF] Bollmann | Morphological variation of Gephyrocapsa oceanica Kamptner 1943 in plankton samples: implications for ecologic and taxonomic interpretations[END_REF][START_REF] Bollmann | The effect of sea water salinity on the morphology of Emiliania huxleyi in plankton and sediment samples[END_REF][START_REF] Triantaphyllou | Seasonal variation in Emiliania huxleyi coccolith morphology and calcification in the Aegean Sea (Eastern Mediterranean)[END_REF]. In deeper time, studies are more problematic due to difficulties in the reconstruction of the paleoenvironmental conditions and the effects of preservation in the fossil assemblages.

Despite this, factors such as sea-water temperature (e.g., [START_REF] Bornemann | Size analyses of the coccolith species Biscutum constans and Watznaueria barnesiae from the Late Albian "Niveau Breistroffer" (SE France): taxonomic and palaeoecological implications[END_REF][START_REF] Linnert | Biometry of Cenomanian-Turonian placoliths: a proxy for changes of fertility and surface-water temperature?[END_REF][START_REF] Wulff | Size variations and abundance patterns of calcareous nannofossils in mid Barremian black shales of the Boreal Realm (Lower Saxony Basin)[END_REF], nutrient (e.g., [START_REF] Erba | Campanian dwarf calcareous nannofossils from the Wodejebato Guyot[END_REF][START_REF] Giraud | Paleoenvironmental controls on the morphology and abundance of the coccolith Watznaueria britannica (Late Jurassic, southern Germany)[END_REF][START_REF] Linnert | Biometry of Cenomanian-Turonian placoliths: a proxy for changes of fertility and surface-water temperature?[END_REF][START_REF] Lübke | Size variations of coccoliths in Cretaceous oceans -A result of preservation, genetics and ecology?[END_REF][START_REF] Wulff | Size variations and abundance patterns of calcareous nannofossils in mid Barremian black shales of the Boreal Realm (Lower Saxony Basin)[END_REF] and light availability (e.g., [START_REF] Lübke | Size variations of coccoliths in Cretaceous oceans -A result of preservation, genetics and ecology?[END_REF][START_REF] Lübke | The impact of OAE 1a on marine biota deciphered by size variations of coccoliths[END_REF],

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Journal Pre-proof acidification (e.g., [START_REF] Erba | Calcareous nannoplankton response to surface-water acidification around Oceanic Anoxic Event 1a[END_REF], or trace metal-and CO 2 water concentrations (e.g., [START_REF] Faucher | Calcareous nannoplankton response to the latest Cenomanian Oceanic Anoxic Event 2 perturbation[END_REF] are thought to have influenced coccolith growth and calcification.

Coccolith size change in the fossil record has been also attributed to evolutionary processes [START_REF] López-Otálvaro | Discorhabdus as a key coccolith genus for paleoenvironmental reconstructions (Middle Jurassic, Lusitanian Basin): Biometry and taxonomic status[END_REF][START_REF] Gollain | Size patterns of the coccolith Watznaueria barnesiae in the lower Cretaceous: Biotic versus abiotic forcing[END_REF]. Changes toward decreasing size are usually claimed to represent a response to stressful and unstable environmental conditions (eutrophication, lower temperature and light availability, increased CO 2 concentrations and acidification) in some fossil coccolith species, while other taxa do not show size alterations. Long-term size increases are however claimed to be related to evolutionary processes. Since most of the observed biometric changes in this study (e.g., in Flabellites oblongus, in the new Lithraphidites morphospecies and in the Hayesites irregularis gr.) represent mainly long-term size increases, they are interpreted as related to evolutionary processes.

The biometric studies cited above were all performed on coccolith species. However, most of the biometric data presented in this study correspond to nannoliths whose possible relationship with coccoliths is uncertain and whose ecological preferences are mostly unknown. However, our data suggest that some link existed between morphologic change/evolutionary patterns and paleogeography. Here we review the morphoevolutionary trends of selected nannofossil groups in relation to the latest Barremian-Aptian paleogeographic changes.

The genus Lithraphidites first appeared in the Berriasian (e.g., [START_REF] Perch-Nielsen | Mesozoic calcareous nannofossils[END_REF] and consist of bladed rod-shaped nannoliths that taper towards both ends, have a cruciform

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Journal Pre-proof cross-section and may have a minute basal murolith coccolith. Janin (1988) suggested affinities of these nannoliths with Actinozoa that most authors do not find compelling, and it is currently thought that they may represent disarticulated spines of a heterococcolith (https://www.mikrotax.org/system/index.php?taxon=Lithraphidites&module=ntax_mes ozoic).

A common evolutionary trend within the genus Lithraphidites consists of a widening of the longitudinal blades in a symmetrical or asymmetrical way. This trend episodically originated in several species across the Cretaceous (e.g., L. houghtonii and L. morayfirthensis in the Aptian; L. alatus, L. acutus and L. eccentricus in the Albian-Cenomanian; L. praequadratus, L. quadratus and L. kennethii in the Campanian-Maastrichtian). The current work shows this trend also operated on the Tethyan-Atlantic Lithraphidites across the latest early Barremian-late Barremian (Figs. 11,12,13), leading to the differentiation of three species (L. aichmoides, L. pugio and L. magnus; Chapter 6). These constitute the earlier known record of this evolutionary trend within the genus Lithraphidites.

Besides the Subbetic Domain, L. magnus was recorded in the North American Basin [START_REF] Covington | Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep sea fan complex: Deep Sea Drilling Project Leg 93, Site 603, lower continental rise off Cape Hatteras[END_REF], West Iberian Continental Margin [START_REF] Bralower | Timing and palaeoceanography of oceanic dysoxia/anoxia in the Late Barremian to Early Aptian (Early Cretaceous)[END_REF] and northern Gargano (Cobianchi et al., 1997). This suggests a westernmost Tethys-North Atlantic paleogeographic record for this species (Fig. 2). The records of L. aichmoides and L. pugio are so far limited to the Subbetic as both are new species described in the current work and remain undifferentiated from L. magnus in the previous papers.

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Lithraphidites houghtonii is a species with a very similar morphology to L. pugio/L. magnus, but being noticeably smaller (length 9-12 µm). It was recorded [START_REF] Jeremiah | A Lower Cretaceous nannofossil zonation for the North Sea Basin[END_REF][START_REF] Bottini | Integrated stratigraphy of Early Aptian black shales in the Boreal Realm: calcareous nannofossil and stable isotope evidence for global and regional processes[END_REF] throughout the lower Aptian (uppermost part of Prodeshayesites fissicostatus AZ) to lower upper Aptian of the North Sea area and Lower Saxony Basin (Fig. 2). As the evolutionary lineage defined by the Tethyan-Atlantic L. aichmoides-L. pugio-L. magnus is earlier, we speculate these taxa (especially L. magnus) could be the ancestors of the Boreal species. In relation to this, the latest Barremian-early Aptian paleogeography (Fig. 2), together with sea level rise (e.g., [START_REF] Hallam | Phanerozoic Sea Level Changes[END_REF]Mutterlose, 1992b;[START_REF] Mutterlose | Calcareous nannofossil paleoceanography of the Early Cretaceous of NW Europe[END_REF][START_REF] Hardenbol | Mesozoic and Cenozoic sequence and chronostratigraphic framework of European basins[END_REF][START_REF] Mutterlose | The Barremian -Aptian interval in NW Germany: a review[END_REF] would have allowed the migration of some populations of L. magnus into the North Sea Basin, where they evolved into L. houghtonii (Fig. 11). Several authors record a homogenization followed by a Tethyan influx of marine invertebrate faunas [START_REF] Mutterlose | Calcareous nannofossils and belemnites as warmwater indicators from the NW-German Middle Aptian[END_REF][START_REF] Mutterlose | The Barremian-Aptian turnover of biota in northwestern Europe: evidence from belemnites[END_REF][START_REF] Mutterlose | The Barremian -Aptian interval in NW Germany: a review[END_REF] and calcareous nannofloras [START_REF] Mutterlose | Calcareous nannofossils and belemnites as warmwater indicators from the NW-German Middle Aptian[END_REF][START_REF] Mutterlose | Temperature-controlled migration of calcareous nannofloras in the north-west European Aptian[END_REF](Mutterlose, , 1992a[START_REF] Mutterlose | Calcareous nannofossil paleoceanography of the Early Cretaceous of NW Europe[END_REF][START_REF] Jeremiah | A Lower Cretaceous nannofossil zonation for the North Sea Basin[END_REF] into the West European Province (WEP) of the Boreal Realm throughout the early Aptian, which gives additional support to the suggested migration.

The marker species Flabellites oblongus and Hayesites irregularis gr. also underwent morphologic changes across the late Barremian-early Aptian here interpreted as the result of long-term evolutionary processes. The early coccoliths of F. oblongus are small, progressively increasing to medium size from the Gerhardtia provincialis ASz upwards (Figs. 8, 9; see [START_REF] Aguado | Biostratigraphic events at the Barremian/Aptian boundary in the Betic Cordillera (southern Spain)[END_REF][START_REF] Bown | Early to mid-Cretaceous calcareous nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise[END_REF]. Regarding the H. irregularis gr., aside from the two morphotypes identified by mixture analyses (Chapter 4.2, 6; Fig. 7), a gradual increase in size has been observed in the specimens of H. irregularis s.str.

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Journal Pre-proof across the Martelites sarasini AZ (SM2). The LOs of F. oblongus and H. irregularis are often recorded, as rare species, from the lower Aptian interval (Prodeshayesites fissicostatus/tenuicostatus-Deshayesites forbesi AZs) in the WEP of the Boreal Realm (e.g., [START_REF] Erba | The Aptian Stage[END_REF]Bown et al., 1998;[START_REF] Mutterlose | The Barremian -Aptian interval in NW Germany: a review[END_REF][START_REF] Jeremiah | A Lower Cretaceous nannofossil zonation for the North Sea Basin[END_REF]. However, these records correspond to the entry of the species in the Boreal Realm, which is concomitant with the homogenization of floras and faunas and Tethyan influx described above, and do not correspond to the true LOs of these species.

During the late Barremian, the WEP of the Boreal Realm and the Tethyan Realm were nearly isolated from each other (e.g., Ziegler, 1990;Mutterlose, 1992b;[START_REF] Barrier | Paleotectonic Reconstruction of the Central Tethyan Realm[END_REF]. However, Jeremiah (2001) recorded short influxes of Micrantholithus stellatus in rocks equivalent to the uppermost Barremian Parancyloceras bidentatum AZ in the North Sea Basin (Fig. 2). The LO of M. stellatus in the Subbetic Domain has been recorded in the upper part of the Gerhardtia provincialis ASz (see chapters 4.3 and 5.1, Fig. 9), that is, much earlier that its occurrence in the North Sea Basin. Based on its morphological similarities with the extant species Braarudosphaera bigelowii, the genus Micrantholithus is commonly interpreted as a marginal/neritic taxon (e.g., [START_REF] Roth | Distribution of coccoliths in oceanic sediments[END_REF][START_REF] Applegate | Lower Cretaceous calcareous nannofossils from continental margin drill sites off North Carolina (DSDP Leg 93) and Portugal (ODP Leg 103): a comparison[END_REF][START_REF] Street | Palaeobiogeography of Early Cretaceous (Berriasian-Barremian) calcareous nannoplankton[END_REF][START_REF] Bown | Early to mid-Cretaceous calcareous nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise[END_REF][START_REF] Bottini | Integrated stratigraphy of Early Aptian black shales in the Boreal Realm: calcareous nannofossil and stable isotope evidence for global and regional processes[END_REF][START_REF] Quijano | Organic geochemistry, stable isotopes, and J o u r n a l P r e -p r o o f Journal Pre-proof facies analysis of the Early Aptian OAE -New records from Spain (Western Tethys)[END_REF]Aguado et al., 2014a, b). The short influxes of M. stellatus in the North Sea Basin suggest that shallow seaways intermittently connected the WEP of the Boreal Realm and the Tethyan Realm already during the late Barremian, favoring the expansion of Tethyan neritic nannofloras into the Boreal Realm. As no Boreal taxa were recorded in our sections during this interval, we suggest this influx of neritic Tethyan taxa (M. stellatus) into the Boreal Realm was probably favored by increasing temperatures related to the Taxy Episode.

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Late Barremian episodes of sea isolation, coincident with regressive periods, favored the allopatric speciation of calcareous nannoplankton and the apparition of endemic taxa under restricted conditions, (e.g., in the WEP of the Boreal Realm; [START_REF] Jakubowski | A proposed Lower Cretaceous nannofossil zonation scheme for the Moray Firth area of the North Sea[END_REF][START_REF] Crux | Biostratigraphy and palaeogeographical applications of Lower Cretaceous nannofossils from north-western Europe[END_REF]Bown et al., 1998;[START_REF] Jeremiah | A Lower Cretaceous nannofossil zonation for the North Sea Basin[END_REF]. During moderate to extensive high stands, seaways opened improving the communication between the Tethyan Realm and the WEP of the Boreal Realm, and nannofloral exchange (e.g., Mutterlose, 1992aMutterlose, , b, 1996)). All the described biogeographic data suggest that paleogeography played a fundamental role in the evolution and spatial distribution of calcareous nannoplankton in the west European-Atlantic region during the late Barremian-early Aptian interval.

Systematic paleontology (by R. Aguado)

The taxonomic descriptions below follow the terminology guidelines of [START_REF] Young | Guidelines for coccolith and calcareous nannofossil terminology[END_REF] and the higher taxonomy follows [START_REF] Bown | Mesozoic calcareous nannoplankton classification[END_REF]. Only taxonomic references that do not appear in [START_REF] Bown | Calcareous Nannofossil Biostratigraphy[END_REF] or cannot be found in the Nannotax website (http://www.mikrotax.org/Nannotax3/) are provided in the reference list. In the following descriptions, L = length, W = width, XPL = cross-polarized light, CNZ /CNSz = calcareous nannofossil Zone/Subzone.

Images and smear slides of type material are stored in the Department of Geology of the University of Jaén (DG image numbers bracketed in the descriptions below). All species names are registered at the Plant Fossil Names Registry (PFNR; https://plantfossilnames.org) of the National Museum Prague. The corresponding PFNR nomenclatural act number is indicated for each new species. The reference calcareous nannofossil biozonation used is that of [START_REF] Bralower | An integrated Cretaceous microfossil biostratigraphy[END_REF], with the modifications

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Journal Pre-proof introduced in this paper. The reference planktonic foraminifera biozonation is that of [START_REF] Coccioni | First radiation of Cretaceous planktonic foraminifera with radially elongate chambers at Angles (Southeastern France) and biostratigraphic implications[END_REF].

Order Podorhabdales Rood et al., 1971, emend. Bown, 1987Family Biscutaceae Black, 1971 Genus Crucibiscutum Jakubowski, 1986 Crucibiscutum bastetanum sp. nov. PFNR: PFN001007.

(Figs. 14A-N) 1997 Crucibiscutum salebrosum Aguado et al., Figs. 8.19, 8.20, 8.22 non Fig. 8.21. 2014a Crucibiscutum hayi Aguado et al., 1987 Cruciplacolithus hayi Covington andWise, Pl. 1, Fig. 6. 1994 Corollithion cf. C. achylosum Bralower et al., Figs. 19.31, 19.32. 1997 Crucibiscutum hayi Aguado et al., Figs. 8.23, 8.24.

Derivation of name: From the Latin word gracilis meaning 'slim', 'slender', 'delicate', referring to the narrow rim and slim axial cross of this species. Type locality: X.HA section, Province of Granada, southeastern Spain.

Occurrence: Found throughout the upper Barremian to lower Aptian (uppermost part of the NC5E1 to NC6A2 CNSzs; lower part of the Gassendiceras alpinum ASz to Hedbergella excelsa Zone of planktonic foraminifera) in sections X.Cp 2, X.F, XF1, X.HA, X.Kv, X.Kv 2 , and RA03 from the Subbetic Domain in the Betic Cordillera (southern Spain). This species was also recorded, as Cruciplacolithus hayi, in DSDP Site 603 off Cape Hatteras by [START_REF] Covington | Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep sea fan complex: Deep Sea Drilling Project Leg 93, Site 603, lower continental rise off Cape Hatteras[END_REF] and as Corollithion cf. C. achylosum across the upper Barremian-lowermost Aptian of the ODP Site 641 by [START_REF] Bralower | Timing and palaeoceanography of oceanic dysoxia/anoxia in the Late Barremian to Early Aptian (Early Cretaceous)[END_REF]. Crucibiscutum hayi, from the Upper Albian, has a greater axial ratio, a wider rim and a central area slightly narrow than that of C. gracile.

Family Cretarhabdaceae [START_REF] Thierstein | Lower Cretaceous calcareous nannoplankton biostratigraphy[END_REF] Genus Flabellites [START_REF] Thierstein | Lower Cretaceous calcareous nannoplankton biostratigraphy[END_REF] Flabellites oblongus (Buky, 1969) Crux in Crux et al., 1982 Remarks: A known morphological trend for the specimens of Flabellites oblongus along the upper Barremian-Albian (e.g., [START_REF] Aguado | Biostratigraphic events at the Barremian/Aptian boundary in the Betic Cordillera (southern Spain)[END_REF][START_REF] Bown | Early to mid-Cretaceous calcareous nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise[END_REF] is the increase in coccolith size. Recently, de [START_REF] De Kaenel | New biostratigraphical data (calcareous nannofossils, ammonites) and Early to Late Barremian transition in the Urgonien Jaune facies and Marnes de la Russille complex of the Swiss Jura Mountains[END_REF] erected a new species (Flabellites eclepensensis) for those small (3 to <5 μm) specimens previously assigned to F. oblongus (e.g., Aguado et al., 2014a). However, the mixture analysis performed in the present study (Chapter 4.1 and Fig. 8) suggest a rather continuous increase in size of the measured population. The selected size of 5 μm by de [START_REF] De Kaenel | New biostratigraphical data (calcareous nannofossils, ammonites) and Early to Late Barremian transition in the Urgonien Jaune facies and Marnes de la Russille complex of the Swiss Jura Mountains[END_REF] to separate the specimens assigned to F. eclepensensis within the complete pool of F. oblongus s.l. seems arbitrary. In the absence of any other distinctive biometric (e.g., ellipticity) or morphological character that could help in a net separation of both species, we opted here to retain the wide concept (F. oblongus s.l., or simply F. oblongus) of the species.

Order Eiffellithales Rood et al, 1971Family Chiastozygaceae Rood et al., 1973Genus Chiastozygus Gartner, 1968 Chiastozygus lamprostauros sp. nov. Aguado et al.,Figs. 15,16. 2014a Chiastozygus litterarius Aguado et al.,.

Derivation of name:

From the Greek words lampros meaning 'bright', and stauros meaning 'cross', 'saltire', referring to the XPL image of this species.

Diagnosis: Small to medium-sized (4.3-7.2 μm) normally elliptical Chiastozygus coccoliths with a narrow (~1.2 μm) rim. The relatively wide central area is covered by a diagonal cross whose arms are seen simple and brighter than the rim when the longitudinal direction is oriented at 45° under XPL.

Description: This species has an axial ratio ~1.4 and a relatively narrow rim, which is dark and diffusely bicyclic under XPL. The diagonal cross spanning the central area have narrow (~0.5 μm) arms that show median lines and remain dark when the longitudinal direction is oriented at 0°. These arms are seen simple (without median lines) and bright under XPL when the longitudinal direction is oriented at 45°. The angle between the arms of the cross is greater (~105°) in the longitudinal direction than in the transverse direction (~75°). The arms of the diagonal cross are asymmetrical (slightly rotated) with respect to the axes of the ellipse. In some specimens, the diagonal cross supports the base of a distal stem. Type locality: X.HA section, Province of Granada, southeastern Spain.

Occurrence: Found, as a rare species, from the upper Barremian (upper part of the NC5E2 CNSz, Gerhardtia sartousiana ASz) to uppermost lower Aptian (NC7A2 CNSz, Deshayesites forbesi AZ). Recorded in sections X.Ag 6 , X.Cp 2, X.F, X.F1, X.HA, X.Kv, X.Kv 2 , and RA03 from the Subbetic Domain in the Betic Cordillera (southern Spain).

Remarks: Rhagodiscus sicutclipeus is rather similar to Rhagodiscus achlyostaurion (upper Aptian-Coniacian) from which differs by its noticeably smaller central spine base, which does not seem hollow and does not reach the internal margin of the rim. Order Watznaueriales Bown, 1987Family Watznaueriaceae Rood et al., 1971Genus Cyclagelosphaera Noël, 1965 Cyclagelosphaera platyaspis sp. nov. PFNR: PFN001010. showing the present-day location of the sections included in this study. A: X.Cp 2 section; B: X.V 1 section; C: X.Kv and X.Kv 2 sections; D: X.Ag 6 section; E: RA03 section; F: X.CT and X.HA sections; G: X.Z section; H: X.F and X.F1 sections; I: X.CO 2 section. and [START_REF] Barrier | Paleotectonic Reconstruction of the Central Tethyan Realm[END_REF]. Location of several areas and sections referenced throughout the text. Sb: Subbetic Basin. 398: DSDP Site 398 [START_REF] Bralower | Timing and palaeoceanography of oceanic dysoxia/anoxia in the Late Barremian to Early Aptian (Early Cretaceous)[END_REF]; 603: DSDP Site 603 [START_REF] Covington | Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep sea fan complex: Deep Sea Drilling Project Leg 93, Site 603, lower continental rise off Cape Hatteras[END_REF]; 641: ODP Site 641 [START_REF] Bralower | Timing and palaeoceanography of oceanic dysoxia/anoxia in the Late Barremian to Early Aptian (Early Cretaceous)[END_REF]; Cg: UK North Sea Central Graben (Well 22/26a-2); Mf: Moray-Firth area (Well 21/2-6); Nj: North Jens-1 Well; Sp: Speeton cliffs (see [START_REF] Jeremiah | A Lower Cretaceous nannofossil zonation for the North Sea Basin[END_REF]. Gp: Gargano Promontory [START_REF] Channell | Early Cretaceous magnetic stratigraphy in the APTICORE drill core and adjacent outcrop at Cismon (Southern Alps, Italy), and correlation to the proposed Barremian-Aptian boundary stratotype[END_REF]; Ls: Lower Saxony Basin [START_REF] Malkoč | Timing of the Early Aptian δ 13 C excursion in the Boreal Realm[END_REF]. Regression lines considering all specimens (solid) and the separated populations of H. irregularis s.str. and H. irregularis E (dashed). C) Frequency histogram showing the distribution curves resulting from a mixture analysis applied to the L/W ratio of all measured specimens. The small table shows the descriptive statistical parameters (proportion, mean, and standard deviation) resulting from the mixture analysis. Two populations are revealed based on the L/W ratio. The forms with L/W > 1.12 were assigned to H. irregularis E. See text for details. Data for X.Kv 2 section after [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF] and this paper; data for Cassis-La Bédoule after [START_REF] Kuhnt | Carbon isotope stratigraphy of the lower Aptian historical stratotype at Cassis-La Bédoule (SE France)[END_REF] and Moullade et al. (1998a); data for Angles after J o u r n a l P r e -p r o o f Journal Pre-proof [START_REF] Delanoy | About some significant ammonites from the Lower Aptian (Bedoulian) of the Angles-Barrême area (South-East France)[END_REF], [START_REF] Wissler | Chemostratigraphic correlation of Barremian and lower Aptian ammonite zones and magnetic reversals[END_REF] and [START_REF] Godet | Evolution of marine stable J o u r n a l P r e -p r o o f Journal Pre-proof carbon-isotope record during the early Cretaceous: A focus on late Hauterivian and Barremian in the Tethyan realm[END_REF]; data for Gorgo a Cerbara after [START_REF] Stein | Progressive palaeoenvironmental change during the Late Barremian-Early Aptian as prelude to Oceanic Anoxic Event 1a: Evidence from the Gorgo a Cerbara section (Umbria-Marche basin, central Italy)[END_REF]Stein et al. ( , 2012) ) and [START_REF] Frau | The Aptian GSSP candidate at Gorgo a Cerbara (Central Italy): an alternative interpretation of the bio-, litho-and chemostratigraphic markers[END_REF]. In Angles section, the boundary between Martelites sarasini and Deshayesites oglanlensis AZs marked with a star is after [START_REF] Godet | Evolution of marine stable J o u r n a l P r e -p r o o f Journal Pre-proof carbon-isotope record during the early Cretaceous: A focus on late Hauterivian and Barremian in the Tethyan realm[END_REF], the boundary marked with two stars (bed 197b) is after [START_REF] Delanoy | About some significant ammonites from the Lower Aptian (Bedoulian) of the Angles-Barrême area (South-East France)[END_REF], and reinterpreted here following [START_REF] Reboulet | Report on the 4th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the "Kilian Group[END_REF]. (2020). Calcareous nannofossil zones/subzones follow [START_REF] Bralower | An integrated Cretaceous microfossil biostratigraphy[END_REF] and modifications proposed in this work. Tethyan ammonite zones after [START_REF] Reboulet | Report on the 6th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the Kilian Group[END_REF]. NW Europe ammonite zones follow Mutterlose (1992b), Casey et al. (1998), [START_REF] Mutterlose | The Barremian -Aptian interval in NW Germany: a review[END_REF], [START_REF] Malkoč | Timing of the Early Aptian δ 13 C excursion in the Boreal Realm[END_REF], and [START_REF] Bottini | Integrated stratigraphy of Early Aptian black shales in the Boreal Realm: calcareous nannofossil and stable isotope evidence for global and regional processes[END_REF].

Rhagodiscus pancostii (Lower

Stratigraphic range of Lithraphidites houghtonii and Lithraphidites moray-firthensis

after [START_REF] Jeremiah | A Lower Cretaceous nannofossil zonation for the North Sea Basin[END_REF] and [START_REF] Bottini | Integrated stratigraphy of Early Aptian black shales in the Boreal Realm: calcareous nannofossil and stable isotope evidence for global and regional processes[END_REF]. Sea-level curves (dashed line = long-term; continuous line = short-term) after [START_REF] Hardenbol | Mesozoic and Cenozoic sequence and chronostratigraphic framework of European basins[END_REF]. MBE = Mid-Barremian Episode, TE = Taxy Episode, ISNE = C-isotope Intra-Sarasini Negative Excursion. Duration of the MBE, TE and ISNE after [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF]. Duration of the OAE 1a after [START_REF] Li | Toward an orbital chronology for the early Aptian Oceanic Anoxic Event (OAE1a, ~120 Ma)[END_REF], [START_REF] Malinverno | Orbital tuning as an inverse problem: Chronology of the early Aptian oceanic anoxic event 1a (Selli Level) in the Cismon APTICORE[END_REF] and [START_REF] Giraud | The palaeoceanographic crisis of the Early Aptian (OAE 1a) in the Vocontian Basin (SE France)[END_REF].

  Lithraphidites aichmoides, followed by the successive LOs of Lithraphidites magnus, Crucibiscutum bastetanum and Nannoconus sp. cf. N. truittii (Hemihoplites feraudianus ASz). -LO of Hayesites irregularis s. str. (Imerites giraudi AZ) -LO of Stoverius acutus, followed by the wc>nc Event and the HO of Crucibiscutum bastetanum (lower part of the Martelites sarasini AZ).-LOs of Nannoconus truittii and Rhagodiscus angustus (Deshayesites oglanlensis AZ).

  J o u r n a l P r e -p r o o f Journal Pre-proof -Presence of Conusphaera rothii and Micrantholithus stellatus (lower part of the Deshayesites forbesi AZ).

  have stratigraphic value, several of them (e.g., Chiastozygus lamprostauros, Crucibiscutum gracile, Lithraphidites magnus, Nannoconus sp. cf. N. truittii, Phosterolithus prossii, Rhagodiscus sicutclipeus and Stoverius acutus) are rare and/or have a spotty and discontinuous record (drawn in dashed line in Fig. 9) throughout a substantial part of their respective stratigraphic ranges. Other taxa have unclear LOs due to the presence of transitional morphologies in the stratigraphic record. Such is the case of the LOs of Rhagodiscus gallagheri (obscured by the presence of transitional forms from small Rhagodiscus asper) and Lithraphidites magnus (difficult to differentiate from transitional specimens from Lithraphidites pugio in the upper part of the Hemihoplites feraudianus ASz). The LO of Nannoconus truittii (upper part of Deshayesites oglanlensis AZ) is masked by the record of forms similar to this species reported here as Nannoconus sp. cf. N. truittii (see Chapter 6: Figures 3, 4, and range charts of SM2). Finally, specimens of Rhagodiscus gallagheri transitional to Rhagodiscus angustus were observed from the upper part of the Martelites sarasini AZ. The oldest forms assignable to R. angustus were recorded from the uppermost part of J o u r n a l P r e -p r o o f Journal Pre-proof the Deshayesites oglanlensis/lowermost Deshayesites forbesi AZs upwards, which agrees with the observations of

  Top: LO of Lithraphidites pugio (calibrated to 123.57 Ma). Age and stratigraphic range: Latest early Barremian-earliest late Barremian (upper part of the Holcodiscus caillaudianus ASz-lower part of the Gassendiceras alpinum ASz). This subzone has a duration of 1.15 myr following the chronostratigraphy of Martinez et al. (2020). NC5E2 Subzone. (New subzone) Base: LO of L. pugio. Top: LO of Micrantholithus stellatus (calibrated to 122.64 Ma). J o u r n a l P r e -p r o o f Journal Pre-proof Age and stratigraphic range: Mid-part of the late Barremian (lower part of the G. alpinum ASz-upper part of the Gerhardtia provincialis ASz). Duration of 0.93 myr according to Martinez et al. (2020). NC5E3 Subzone. (New subzone) Base: LO of M. stellatus. Top: LO of Hayesites irregularis E (calibrated here to 122.45 Ma), slightly earlier than in Martinez et al., (2020). Age and stratigraphic range: Mid-part of the late Barremian (upper part of the G. provincialis ASz-lower part of the Hemihoplites feraudianus ASz). Duration of 0.19 myr following Martinez et al. (2020). NC6A1 Subzone. (New subzone) Base: LO of H. irregularis E. Top: HO of Crucibiscutum bastetanum (calibrated here to 121.97 Ma). Age and stratigraphic range: Upper part of the late Barremian (lower part of H. feraudianus ASz-lower part of Martelites sarasini AZ). Duration of 0.48 myr following Martinez et al. (2020). NC6A2 Subzone. (New subzone) Base: HO of C. bastetanum. Top: HO of Conusphaera rothii. Age and stratigraphic range: Latest Barremian-early Aptian (lower part of the M.sarasini AZ-Hedbergella excelsa). This subzone has a duration much greater than 0.97 myr following[START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF].

  J o u r n a l P r e -p r o o f Journal Pre-proof 5.3. Calcareous nannofossil bioevents, C-isotope stratigraphy and the Barremian/Aptian boundary: an update

  10. 2014b Crucibiscutum hayi Aguado et al., Fig. 3.15. Derivation of name: After the Bastetani, an old Iberian tribe that populated the southeastern part of the Iberian Peninsula, the type area of this species. Diagnosis: Small to medium-sized (3.4-5.5 μm) broadly elliptical to normally elliptical Crucibiscutum coccoliths with a relatively narrow central area spanned by off-axial (slightly rotated) cross bars. The rim is bicyclic, with the bright inner cycle being wider (~1 μm width) than the outer dark cycle. Description: Under XPL, the bright inner cycle of the rim has equal or greater width than the outer dark cycle. The central area is nearly filled by a relatively thick cross slightly rotated with respect to the axes of the ellipse defined by the rim. The cross is bright (although not as bright as the inner cycle of the rim) under XPL when oriented at 45°, and dark when oriented to 0°. The long and short arms of the central cross usually have slightly different rotation. J o u r n a l P r e -p r o o f Journal Pre-proof Dimensions: L = 3.4-5.5 (average 4.6) μm; W = 2.9-4.5 (average 3.8) μm; specimens measured: 22. Holotype: Figs. 14A, B [DG2802, DG2803] (are same specimen). Holotype dimensions: L = 4.9 μm, W =3.9 μm. Paratypes: Figs. 14C, D [DG2804, DG2805] (are same specimen); Figs. 14E, F [DG2806, DG2807] (are same specimen). Type level: Uppermost Barremian, sample X.HA-2 [DGF001] (NC6A1) nannofossil Subzone; upper part of Imerites giraudi AZ). Type locality: X.HA section, Province of Granada, southeastern Spain. Occurrence: This species has a short range. Its LO was found near the top of the Gerhardtia sartousiana AZ, (upper part of the Hemihoplites feraudianus ASz), which is equivalent to the lowermost part of the NC6A1 CNSz, and is shortly preceded by the LO of the primitive forms (elongated) of Hayesites irregularis E. Its HO was recorded in the lower part of the Martelites sarasini AZ (upper boundary of the NC6A1 CNSz), shortly following the nc>wc Event (Chapter 4.3, Fig. 9). Usually this species is a rare component of the assemblages, being more abundant from the upper part of the Imerites giraudi AZ to its HO, but shows a rather consistent record. It was recorded in sections X.Ag 6 , X.F, X.F1, X.HA, X.Kv, X.Kv 2 , and RA03 from the Subbetic Domain in the Betic Cordillera (southern Spain). Its HO is used here to define the upper boundary of the NC6A1 CNSz. Remarks: Crucibiscutum bastetanum differs from Crucibiscutum salebrosum (Berriasian-Hauterivian), Crucibiscutum ryazanicum (Berriasian-Valanginian) and Crucibiscutum pinnatus (Hauterivian-Barremian) by having a rim with a wider (~1 μm) bright inner cycle when viewed in XPL and a slightly larger size. Crucibiscutum salebrosum has, in addition, a cross aligned with the axes of the ellipse instead of a J o u r n a l P r e -p r o o f Journal Pre-proof slightly rotated one as in C. bastetanum. Crucibiscutum bastetanum differs from Crucibiscutum neuquenensis (lower Hauterivian) and Crucibiscutum trilensis (upper Hauterivian) by having a narrower central area, which is nearly filled by a relatively thick cross, and a wider (~1 μm) bright cycle of the rim when viewed in XPL. Crucibiscutum hayi (Upper Albian) and Crucibiscutum gracile (below) have wider (more open) central areas and narrower axial cross bars. Palaeopontosphaera giraudii (de Kaenel, 2020) has a greater size, with a bright inner cycle of the rim of similar width to the outer dark cycle, and an axial cross. Following de Kaenel et al. (2020), the range of P. giraudii is early Hauterivian-late Barremian (HO in T. vandenheckii AZ), being earlier in time than C. bastetanum and there is a stratigraphical displacement between these two species. Crucibiscutum gracile sp. nov. PFNR: PFN001008. (Figs. 14O-AB)

Diagnosis:

  Small (3.4-4.7 μm) sub-circular to broadly elliptical (axial ratio ~1.1) Crucibiscutum coccoliths with a wide central area spanned by slim axial cross bars. The rim is narrow, bicyclic, with the bright inner cycle being usually slightly narrower (~0.5 μm width) than the outer dark cycle. J o u r n a l P r e -p r o o f Journal Pre-proof Description: The central area is wide (around twice as wide as the rim width) and partially covered by a slim bright cross with arms aligned with respect to the axes of the ellipse defined by the rim. The central cross is slightly brighter under XPL when oriented at 45º than when oriented to 0°. Dimensions: L = 3.4-4.7 (average 4.1) μm; W = 3.2-4.4 (average 3.8) μm; specimens measured: 20. Holotype: Figs. 14O, P [DG2808, DG2809] (are same specimen). Holotype dimensions: L = 4.4 μm, W = 4.2 μm. Paratypes: Figs. 14Q [DG2810]; Figs. 14R, S [DG2811, DG2812] (are same specimen). Type level: Uppermost Barremian, sample X.HA-2 [DGF001] (NC6A1) nannofossil Subzone; upper part of the Imerites giraudi AZ.

  Remarks: Crucibiscutum gracile differs from all previously described Neocomian Crucibiscutum species (C. giraudii, C. neuquenensis, C. pinnatus, C. ryazanicum, C. salebrosum, C. trilensis) including C. bastetanum (above) by having a wider central area and a narrower rim with a lower axial ratio (~ 1.1), usually showing a sub-circular outline. Crucibiscutum gracile also differs from C. bastetanum, C. trilensis, and C. J o u r n a l P r e -p r o o f Journal Pre-proof ryazanicum in having an axial slim cross spanning the central area. Crucibiscutum gracile has lower axial ratio and a wider and open central area than C. pinnatus.

1997

  Chiastozygus sp. cf. C. litterarius

Family2014a

  Dimensions: L = 4.3-7.2 (average 5.6) μm; W = 3.4-5.5 (average 4.2) μm; specimens measured: 20. Holotype: Figs. 14AC, AD [DG2813, DG2814] (are same specimen). Holotype dimensions: L = 6.2 μm, W = 5.0 μm. J o u r n a l P r e -p r o o f Journal Pre-proof Paratypes: Figs. 14AE, AF [DG2815, DG2816] (are same specimen); Figs. 14AL, AM [DG2817, DG2818] (are same specimen). Type level: Uppermost Barremian, sample X.HA-7 [DGF002] (NC6A2 CNSz; Martelites sarasini AZ).Type locality: X.HA section, Province of Granada, southeastern Spain.Occurrence: Found, as a rare species, from the upper Barremian (upper part of the NC5E2 CNSz, Gerhardtia provincialis ASz) to uppermost lower Aptian (NC7A2 CNSz, Schackoina cabri Zone of planktonic foraminifera). Recorded in sections X.Cp 2, X.F, X.F1, X.HA, X.Kv, X.Kv 2 , and RA03 from the Subbetic Domain in the Betic Cordillera (southern Spain). Remarks: Chiastozygus lamprostauros is rather similar to Chiastozygus amphipons (Santonian-Maastrichtian) in rim construction and optical behavior from which is differentiated by having the arms of the diagonal cross slightly rotated with respect to the axes of the ellipse (asymmetric). It differs from Chiastozygus bifarius (Albian-Maastrichtian) and Chiastozygus platyrhethus (Aptian-Coniacian) by having a narrower, simple (with no median lines when oriented at 45°) diagonal cross with slightly asymmetrical (rotated) arms with respect to the axes of the ellipse. Chiastozygus litterarius (Aptian-Maastrichtian) is a rather poorly documented taxon originally described from the upper Maastrichtian sedimentary successions of Poland, and is characterized by having a weakly birefringent diagonal cross instead of the bright cross when oriented at 45° which is present in C. lamprostauros. Chiastozygus tenuis (another poorly documented species) has a slim diagonal cross symmetrical with respect of the axes of the ellipse instead of a broader, slightly rotated one as present in C. lamprostauros. Chiastozygus lamprostauros differs from other species of this genus (C. antiquus, C. garrisoni, C. stylesii and C. trabalis) by having a dark diffusely bicyclic J o u r n a l P r e -p r o o f Journal Pre-proof rim. Probably most of the late Barremian-early Aptian C. litterarius specimens from the literature should be assigned to C. lamprostauros. Rhagodiscus sp. cf. R. achlyostaurion Aguado et al., Figs. 3.48-50. 2014b Rhagodiscus sp. cf. R. achlyostaurion Aguado et al., Fig. 3.3. Derivation of name: From the Latin words sicut meaning 'as', 'such as', and clipeus, the elliptical war shield used by the ancient Greeks and Romans which resembles the XPL image of this species. Diagnosis: Small to medium-sized (4.6-5.9 μm) normally elliptical Rhagodiscus coccoliths with a relatively wide central area bearing a small spine base, which is bright in XPL. The rim and central area images are distinctly dark in XPL. Description: This species has an elliptic rim (axial ratio ~1.4) and central area that remain relatively dark under XPL. The central area bears a small spine base, which is seen as a bright, solid (not hollow) circle traversed by four sharp extinction gyres. The spine base is relatively small (~1.3 μm in diameter), remains isolated in the middle of the central area and does not reach the internal margin of the rim. Dimensions: L = 4.6-5.9 (average 5.1) μm; W = 3.3-4.6 (average 3.7) μm; specimens measured: 20. Holotype: Fig. 14AQ [DG2819]. Holotype dimensions: L = 5.3 μm, W = 3.7 μm. J o u r n a l P r e -p r o o f Journal Pre-proof Paratypes: Figs. 14AR, AS [DG2820, DG2821]. Type level: Upper Barremian, sample X.HA-4 [DGF003] (NC6A1 CNSz; Martelites sarasini AZ).

  Turonian) is smaller in size (holotype length = 3.96 μm) and lacks the distinctly optical features present in the rim and central area of R. sicutclipeus. Rhagodiscus hamptonii (upper Aptian-Upper Albian) is greater in size and has a less clearly defined (usually absent) bright spine base. Rhagodiscus buisensis lacks the solid birefringent spine base (de Kaenel et al., 2020) present in R. sicutclipeus. Probably most of the Barremian-lower Aptian occurrences of R. achlyostaurion cited in the literature correspond to R. sicutclipeus.

  J o u r n a l P r e -p r o o f magnetochron M0r (a proposed Barremian-Aptian boundary marker) begins at 121.2 ± 0.4 Ma. Geology 49. https://doi.org/10.1130/G48591.1. Ziegler, P.A., 1990. Geological Atlas of Western and Central Europe. Shell Internationale Petroleum Mij. B.V. and Geological Society, London, 239 p.

Figure 1 .

 1 Figure 1. Geologic sketch of the central and eastern sectors of the Betic Cordillera,

Figure 2 .

 2 Figure 2. Paleogeographic map of the Western Tethys-Atlantic connection for the late

Figure 3 .

 3 Figure 3. Lithologic sketches of sections X.V 1 , X.Kv, X.Kv 2 and RA03, with indication

Figure 5 .

 5 Figure 5. Cross-plot of width (W) vs. length (L) for 120 upper Barremian Lithraphidites

Figure 6 .

 6 Figure 6. Cross-plot of length/width (L/W) ratio vs. length (L) for 69 Lithraphidites

Figure 8 .

 8 Figure 8. X.-Cross-plot of coccolith length (L) vs. width (W) for 120 specimens of

Figure 9 .

 9 Figure 9. Geochronostratigraphic sketch showing a compilation of the main

Figure 10 .

 10 Figure 10. Correlation of the uppermost Barremian-lowermost Aptian interval of the

Figure 11 .

 11 Figure 11. Proposed morpho-evolutionary sketch for the genus Lithraphidites across the

Figure 12 .

 12 Figure 12. Cross-polarized light micrographs of several specimens of some of the new

Figure 14 .

 14 Figure 14. Cross-polarized light micrographs of several specimens of some of the

Figure 15 .

 15 Figure 15. Cross-polarized light micrographs of several specimens of the Hayesites

Figure 15

 15 Figure15

Acknowledgements

We want to express our gratitude to M.J. Campos, who helped with the processing of smear slides. This study was funded by research projects P20_00783 (Plan Andaluz de Investigación, Desarrollo e Innnovación), CGL2014-52546-P (Ministerio de Ciencia, Innovacíon y Universidades, Spain) and RNM-200 Research Group (Junta de Andalucía, Spain). This study was designed by RA, who performed the calcareous J o u r n a l P r e -p r o o f Journal Pre-proof nannofossil study, wrote the initial draft, and elaborated the figures. All the authors collected the samples in the field. MC and JS provided the ammonite data, and MM the astrochronological calibration. The authors are very grateful to F. Giraud and J. Mutterlose, whose constructive comments led to improvements in the final version of this paper, and to R. Jordan for his helpful editorial assistance.

Derivation of name: From the Greek words platys, meaning 'wide' and aspis meaning 'shield', alluding to the wider distal shield of this species.

Diagnosis: Medium to large-sized (7.0-8.4 μm) Cyclagelosphaera coccoliths having a wide distal shield and a very small (1.1-1.4 μm) central area.

Description: Circular placoliths with proximal and distal shield elements composed by R-units. In distal view, the V-unit forms a narrow distal cycle around the central area and is seen as a thin, dark line under XPL. The central area is very small (1.1-1.4 μm) compared to the distal shield (7.0-8.4 μm), and is completely closed.

Dimensions: W = 7.0-8.4 (average 7.5) μm; specimens measured: 6. Diagnosis: Very large (15.3-25.3 μm) Lithraphidites nannolith having an outline similar to a bladed dagger. In the direction opposite to the 'handle', the outline is slightly convex and decreases its width slowly before tapering toward the point. The maximum width oscillates between 2.7 and 4.1 μm.

Description: Calcareous rods with cruciform cross-section built of long blades of identical optical orientation. The outline is similar to a bladed dagger in which the 'handle' (~1.1 μm width and frequently missing by breakage) is followed by a wider expansion (2.7-4.1 μm width) which slowly decreases its width before tapering toward the point. Type locality: X.Kv 2 section, Province of Murcia, southeastern Spain.

Occurrence: Recorded from the uppermost lower Barremian (upper part of the Moutoniceras moutonianum AZ) to the upper Barremian (uppermost part of the Hemihoplites feraudianus ASz), within NC5E1-NC6A1 CNSzs. This species is a rare component of the assemblages, but has a consistent and continuous record until the uppermost part of the Gerhardtia provincialis ASz. It has been recorded from sections X.CO 2 , X.CT, X.F, X.Kv, X.Kv 2 , and X.V 1 from the Subbetic Domain in the Betic Cordillera (southern Spain). The LO of L. aichmoides has been recorded 467 cm above that of Flabellites oblongus (base of NC5E1 CNSz) in section X.V 1 .

Remarks: Lithraphidites aichmoides differs from L. magnus (emend.) and L. pugio by having a more stylized outline, with a maximum width smaller than 4.5 μm. This width appears as the more appropriate to separate both species according to the measurements made in the present study (Fig. 5). Lithraphidites aichmoides differs from Lithraphidites alatus (Upper Albian-Lower Cenomanian) by having an outline similar to a bladed dagger instead of a 'closed umbrella', the latter decreasing quickly in width from the end close to the 'handle' towards the point. It differs from Lithraphidites houghtonii (Boreal lower-upper Aptian) by having a greater length and a smaller width. [START_REF] Covington | Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep sea fan complex: Deep Sea Drilling Project Leg 93, Site 603, lower continental rise off Cape Hatteras[END_REF] comb. & stat. nov.

Lithraphidites magnus

J o u r n a l P r e -p r o o f

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1987 Lithraphidites alatus ssp. magnus Covington and Wise, Pl. 10, Figs. 3, 4, 8?. 1994 Lithraphidites alatus ssp. magnus Bralower et al., Figs. 20.7, 20.8. 2020 Lithraphidites magnus Martinez et al.,Fig. 4M.

Emended diagnosis: Very large (usually >21 μm) Lithraphidites nannolith having an outline similar to a bladed dagger. The 'handle' (~1.1 μm width and sometimes missing by breakage) is followed by a wider expansion (4.5-7.0 μm width) which nearly maintains its width a long distance (around three fifths of the nannolith length) before tapering toward the point. The maximum width is greater than 4.5 μm and the L/W ratio is greater than 3.5 (average 4.1).

Remarks: Covington and Wise (1987, p. 631) originally described this taxon, but as a subspecies of Lithraphidites alatus (L. alatus ssp. magnus). Lithraphidites magnus is here erected to the category of species because the lack of stratigraphic connection with L. alatus and the existence of morphologic differences between both taxa. While L. magnus is restricted to the uppermost Barremian-lowermost Aptian, L. alatus ranges from Upper Albian to Lower Cenomanian. The original description of L. magnus was based on two SEM micrographs in which specimens are foreshortened due to tilting or partially covered. The estimated holotype dimensions were 5.7 μm width and ~20 μm long. However, the holotype appears to be a broken specimen, its true length probably being ~25 μm. The length in the population measured in the present paper oscillates between 21.2 and 26.2 μm (average 23.8 μm). After a biometric study (Fig. 6), all specimens with L/W ratio smaller than 3.7 (usually with L<21 μm) were here assigned to Lithraphidites pugio n. sp., which is characterized by a wider and shorter outline (see

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Journal Pre-proof below). It seems a width greater than 4.5 μm is also a good value to characterize these forms differentiating them from Lithraphidites aichmoides n. sp. (Fig. 5).

Occurrence: [START_REF] Covington | Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep sea fan complex: Deep Sea Drilling Project Leg 93, Site 603, lower continental rise off Cape Hatteras[END_REF] recorded this taxon in sediments from core 44 of DSDP Hole 603B (North American Basin of North Atlantic). These were dated as lower Aptian, although no convincing evidence supporting this age was provided from calcareous nannofossil assemblages. [START_REF] Bralower | Timing and palaeoceanography of oceanic dysoxia/anoxia in the Late Barremian to Early Aptian (Early Cretaceous)[END_REF] Diagnosis: Very large (13.4-23.5 μm) Lithraphidites nannolith having an outline similar to a short bladed dagger. In the direction opposite to the 'handle', the outline is convex and quickly decreases its width before tapering toward the point. The maximum width oscillates between 4.5 and 8.1 μm.

Description: Calcareous rods with cruciform cross-section built of long blades of identical optical orientation. The outline is similar to a bladed dagger in which the 'handle' (~1.1 μm width and frequently missing by breakage) is followed by a wider expansion (4.5-8.1 μm width) which nearly maintains its width a short distance (around a half of the nannolith length) before quickly tapering toward the point. The L/W ratio is smaller than 3.5 (average 2.9).

Dimensions: L = 13.4-23.5 (average 18.1) μm; W = 4.5-8.1 (average 6.2) μm; Journal Pre-proof record in the assemblages from the X.F, X.HA, X.Kv, X.Kv 2 and X.V 1 sections. [START_REF] Martinez | Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions[END_REF] used the LO of this species to correlate the uppermost part of the X.V 1 and the lowermost part of the X.Kv 2 sections. This bioevent has shown biostratigraphic potential to be used in correlation, at least at a regional scale (chapters 5.1 and 5.2).

Remarks: Lithraphidites pugio differs from L. magnus (emend.) by having a shorter (usually < 21 μm) and wider outline, with an average L/W ratio ~2.9. The expansion of the blades decreases more quickly in L. pugio than in L. magnus. It differs from L.

aichmoides by having a greater width (>4.5 μm) and nearly parallel sides (by around the half of its length) in side view, before tapering at the end. Lithraphidites pugio differs from Lithraphidites alatus (Upper Albian-Lower Cenomanian) by having an outline similar to a short bladed dagger instead of a 'closed umbrella', the latter having a straight to slightly concave outline quickly decreasing in width from the end close to the 'handle' towards the point. [START_REF] Jeremiah | A Lower Cretaceous nannofossil zonation for the North Sea Basin[END_REF] described Lithraphidites houghtonii from the lower-upper Aptian transition (Deshayesites forbesi to Epicheloniceras martinoides AZs) of the Central North Sea. This later species is morphologically rather similar to L. pugio, from which it differs in having a smaller size (length = 9-12 μm, width ~5.6 μm).

Radiate multielement group Genus Hayesites Manivit, 1971

Hayesites irregularis E (Figs. 15A-R

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Journal Pre-proof Diagnosis: Specimens of H. irregularis [START_REF] Roth | Calcareous nannoplankton: Leg 14 of the Deep Sea Drilling Project[END_REF] Applegate et al. in [START_REF] Covington | Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep sea fan complex: Deep Sea Drilling Project Leg 93, Site 603, lower continental rise off Cape Hatteras[END_REF] with an elongated outline (L/W>1.12) usually showing poorly defined radial elements under cross-polarized light microscopy (XPL). See section 4.2 for details.

Description: A mixture analysis performed on the L/W ratio of 140 specimens of the H. irregularis gr. (Fig. 7C andSM2) indicates that two populations are present within this pool. Those forms with nearly circular outline, (L/W smaller or equal to 1.12), being younger in time, were assigned to Hayesites irregularis s.str. Those specimens having a more elongated outline (L/W>1.12), generally showing poorly defined radial elements and being slightly older, were assigned to H. irregularis morphotype E (H. irregularis

E).

Dimensions: L = 2.8-5.3 (average 3.8) μm; W = 2.2-4.3 (average 3.0) μm; specimens measured: 51. Dimensions: L = 5.6-9.9 (average 7.4) μm; W = 8.1-11.9 (average 10.2) μm; specimens measured: 28.

Occurrence: These forms were recorded (Figs. 3,4; sections RA03, X.Ag6, X.CP 2 , X.F, X.F1, X.HA, X.Kv, X.Kv 2 ) from the upper part of the Hemihoplites feraudianus ASz to the Deshayesites forbesi AZ (NC6A1-NC6A2 CNSzs).

Remarks: Nannoconus truittii ssp. frequens and N. truittii ssp. truittii are respectively taller than wide and of similar height than width in side view [START_REF] Brönnimann | Microfossils incertae sedis from the Upper Jurassic and Lower Cretaceous of Cuba[END_REF]Dères and Achéritéguy, 1980), differing from N. sp. cf. N. truittii. Nannoconus truittii ssp.

rectangularis was described from the Albian (Dères and Achéritéguy, 1980), while N. sp. cf. truittii has been recorded form the uppermost Barremian-lower Aptian.

Conclusions

Delaration of competing interest

None.