Romain Vullo
email: romain.vullo@univ-rennes1.fr

Jean-Pierre Archambeau

Gilles Bailly

Pierre Bénéfice

Reassessment of Cosmodus Sauvage, 1879, a poorly known genus of large pycnodont fish (Actinopterygii, Pycnodontiformes) from the Cenomanian (Upper Cretaceous) of Western Europe

Keywords: Actinopterygii, Pycnodontiformes, Coccodontidae, Cosmodus, Dentition, Cenomanian

The large pycnodontiform fish genus Cosmodus Sauvage, 1879 is redescribed on the basis of both historical material and new specimens, and a formal diagnosis is proposed. The vomerine and prearticular dentitions of Cosmodus show a unique combination of characters, including the morphology and ornamentation of the tooth crowns and the number of tooth rows.

. Cosmodus shares some peculiar

Introduction

The order Pycnodontiformes is a widespread group of ray-finned fishes known from the Upper Triassic to the Eocene (e.g., [START_REF] Martín-Abad | Historical patterns of distribution in pycnodontiform and amiiform fishes in the context of moving plates[END_REF]. Although pycnodontiform genera and species should be preferably defined and diagnosed on the basis of complete, articulated skeletons [START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF], isolated vomerine and prearticular dentitions with unique features (or unique combinations of characters) are still regularly used to erect new taxa (e.g., [START_REF] Poyato-Ariza | New pycnodont fish (Arcodonichthys pasiegae gen. et sp. nov.) from the Early Cretaceous of the Basque-Cantabrian Basin, northern Spain[END_REF][START_REF] Shimada | A new gigantic pycnodont fish from the Juana Lopez Member of the Upper Cretaceous Mancos Shale of New Mexico, U.S.A[END_REF][START_REF] Stumpf | Early Jurassic diversification of pycnodontiform fishes (Actinopterygii, Neopterygii) after the end-Triassic extinction event: Evidence from a new genus and species, Grimmenodon aureum[END_REF][START_REF] Vullo | A unique Cretaceous-Paleogene lineage of piranha-jawed pycnodont fishes[END_REF].

The Cenomanian genus Cosmodus, based on isolated dentitions, was erected by Sauvage (1879) to accommodate a large pycnodontiform species that had been previously assigned to the genus Gyrodus (G. carentonensis [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF]. Subsequently, the genus Cosmodus has been unanimously regarded as a junior synonym of the widespread genus Coelodus Heckel, 1854 [START_REF] Woodward | Catalogue of Fossil Fishes in the British Museum (Natural History) -Part III. Containing the Actinopterygian Teleostomi of the Orders Chondrostei (concluded), Protospondyli, Aetheospondyli, and Isospondyli)[END_REF][START_REF] Woodward | The fossil fishes of the English Chalk -Part V[END_REF][START_REF] Woodward | The fossil fishes of the English Wealden and Purbeck formations -Part II[END_REF][START_REF] Priem | Etude des poissons fossiles du Bassin parisien[END_REF][START_REF] Priem | Sur un pycnodonte du Sénonien supérieur de Tunisie[END_REF][START_REF] Priem | Sur des poissons des terrains secondaires du Sud de la France[END_REF][START_REF] Kriwet | New insight into the distribution and palaeobiology of the pycnodont fish Gyrodus[END_REF], although it clearly appears that the former possesses distinctive dentitions with a unique combination of characters. Here, the genus Cosmodus is reassessed and Basin and northern Spain). This material is used here to designate a neotype, to provide a formal diagnosis of the type and only species, Cosmodus carentonensis [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF], and to discuss, by comparison with other taxa, the systematic affinities of the genus.

Institutional abbreviations. APVSM, Association

Geological settings

Type area

The lost type specimen (Fig. 1) described by [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF]Coquand ( , 1860a, b) , b) and Sauvage (1879[START_REF] Sauvage | Notes sur les poissons fossiles (suite)[END_REF] was collected by the naturalist Alphonse T. de Rochebrune at Pont-de-Basseau in Angoulême, Charente department (northern Aquitaine Basin). In their respective descriptions, [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF]Coquand ( , 1860a, b) , b) and Sauvage (1879[START_REF] Sauvage | Notes sur les poissons fossiles (suite)[END_REF] did not provide any information on the exact stratigraphic position of the specimen within the Cenomanian series, indicating only "étage carentonien" [Carentonian Stage] or "étage à Caprina adversa"

[Caprina adversa Stage] (see [START_REF] Francis | Correlation between the North Temperate and Tethyan Realms in the Cenomanian of Western France and the significance of hardground horizons[END_REF]. Since 2000, intensive collecting of Cenomanian vertebrates in the surrounding area of Angoulême has allowed to precisely locate the (Vullo, 2007). It appears that isolated teeth and fragmentary dentitions (MHNLR 2017.10.4) of Cosmodus commonly occur in the marls and clays ("argiles tégulines" of [START_REF] Coquand | Description physique, géologique, paléontologique et minéralogique du département de la Charente -Tome premier[END_REF] of the lower upper Cenomanian lithological units C4 and D (Calycoceras guerangeri Zone; [START_REF] Moreau | Analyse de la transgression cénomanienne sur la bordure nord-occidentale du Bassin de l'Aquitaine[END_REF][START_REF] Néraudeau | Variation in echinoid biodiversity during the Cenomanian-early Turonian transgressive episode in Charentes (France)[END_REF] outcropping in several clay pits ("Le Pas", "Le Mas" and "L'Amas" quarries) opened in a small area southwest of Angoulême (towns of Nersac, La Couronne and Roullet-Saint-Estèphe) (Vullo, 2007) (Fig. 2). These shallow marine deposits have yielded a rich and diverse fossil assemblage [START_REF] Moreau | Analyse de la transgression cénomanienne sur la bordure nord-occidentale du Bassin de l'Aquitaine[END_REF], including abundant oysters (Rhynchostreon suborbiculatum, Rastellum diluvianum, Pycnodonte biauriculata, Ceratostreon flabellatum) (Videt, 2004;Videt and Néraudeau, 2007), rare ammonites (Thomelites cf. lattense; [START_REF] Moreau | Analyse de la transgression cénomanienne sur la bordure nord-occidentale du Bassin de l'Aquitaine[END_REF], brachyuran crabs [START_REF] Collins | A new etyid crab (Crustacea, Decapoda) from the Cenomanian of France[END_REF]Van Bakel, 2013), echinoids, and common vertebrate remains [START_REF] Rage | A new pachyostotic squamate reptile from the Cenomanian of France[END_REF]Vullo, 2007;Vullo et al., 2007;Vullo and Néraudeau, 2009).

In the Charente-Maritime department, about 100 km west of Angoulême, the île Madame cliffs expose the beds of the lower upper Cenomanian lithological units C4 and D (Calycoceras guerangeri Zone) at the place called "Le Puits des Insurgés" (Fig. 2). The fossil assemblage recovered from these shallow transgressive marine deposits is roughly similar to that found in the Angoulême area. However, oysters are less abundant, ammonites are represented by Pseudocalycoceras sp. and plant fragments (conifers) are present (Videt and Néraudeau, 2007). Besides numerous isolated teeth, complete dentitions of Cosmodus (MHNLR 2017.10.1, MHNLR 2017.10.2, MHNLR 2017.10.3) have been collected at "Le Puits des Insurgés". In the île Madame Cenomanian series, a few teeth of Cosmodus have been also found in the underlying marly limestone deposits of the middle Cenomanian subunit C2 and in the overlying sandy oyster bed located at the base of the upper Cenomanian unit E (Fig. 2).

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Other localities

Outside the type area (Charentes region), three additional French Cosmodus specimens are known from the Cenomanian of the Paris Basin. They all correspond to historical specimens that were collected with more or less precise stratigraphic data. The first specimen (unnumbered specimen from the APVSM collection), probably found by Charles Bacheley at the end of the 18 th century (Brignon, 2016: 599) and subsequently communicated by Auguste Le Prévost to Antoine Passy at the beginning of the 19 th century, comes from the lower part of the côte Sainte-Catherine in Rouen (Seine-Maritime department, Normandy) [START_REF] Passy | Description géologique du département de la Seine-Inférieure[END_REF]. This famous locality, which has provided many fossils since the end of the 18 th century, exposes chalky deposits of middle to late Cenomanian age corresponding to the "Craie de Rouen" Formation [START_REF] Lasseur | A relative water-depth model for the Normandy Chalk (Cenomanian-Middle Coniacian, Paris Basin, France) based on facies patterns of metre-scale cycles[END_REF][START_REF] Lasseur | Stratigraphie et paléogéographie du Cénomanien dans le Bassin parisien[END_REF]. It is very likely that this specimen was collected from the middle Cenomanian phosphatic "Horizon de Rouen" (Acanthoceras rhotomagense Zone), although it might also have been found in one of the overlying strata of the Acanthoceras jukesbrownei Zone. The second specimen (MA 70-530) comes from the middle-upper Cenomanian glauconitic chalk ("Craie glauconieuse") of Seignelay (Yonne department, Burgundy) (Sauvage, 1879). The third specimen (MHNLM 2013.0.2.21) comes from Coulaines near Le Mans (Sarthe department, Maine), a classic fossil-rich locality which was exposing the middle Cenomanian Jalais sandstone and hardground, at the top of the "Sables et grès du Mans" (Acanthoceras jukesbrownei Zone) [START_REF] Morel | La stratigraphie du Cénomanien de la Sarthe[END_REF]Vullo, 2015).

Geographic and stratigraphic information about the previously published specimens from England and Spain is provided by [START_REF] Friedman | The English Chalk and London Clay: two remarkable British bony fish Lagerstätten[END_REF] and Vullo et al. (2009), respectively. The specimen from Halling (Kent, southeastern England), which is the type of subglobosus Zone (Lower Chalk, Grey Chalk Group; middle part of the Zig Zag Chalk Formation; upper middle to lower upper Cenomanian) according to [START_REF] Friedman | The English Chalk and London Clay: two remarkable British bony fish Lagerstätten[END_REF].

Specimen MGM-2504C from Tiroco (Asturias, northern Spain) comes from the La Cabaña Formation, which is middle?-late Cenomanian in age. Interestingly, MGM-2504C was found in association with the ammonite Neolobites vibrayeanus [START_REF] Almela | Investigación del Hullero bajo los terrenos mesozoicos de la Costa Cantábrica (zona de Oviedo-Gijón-Villaviciosa-Infiesto). Empresa Nacional[END_REF]. This ammonite is the index species of a zone partially equivalent to the lower upper Cenomanian Calycoceras guerangeri Zone (Barroso- [START_REF] Barroso-Barcenilla | Ammonite zonation of the upper Cenomanian and lower Turonian in the Iberian Trough, Spain[END_REF]. In Asturias, some jaw fragments and isolated teeth of Cosmodus have also been collected from coeval beds of the La Cabaña and El Toral quarries near Oviedo (Vullo et al., 2009). An additional, previously unpublished specimen (MCNA registration number pending) comes from the upper Cenomanian of Sóbron (Álava, Basque Country, northern Spain). The geological setting of this area and the Sóbron section are described in detail in [START_REF] Floquet | Correlation of sedimentary events during the latest Cenomanian from the Basque Basin to the Castilian Ramp (Northern Spain)[END_REF].

Systematic palaeontology

Osteichthyes Huxley, 1880

Actinopterygii [START_REF] Cope | Zittel's Manual of Palaeontology[END_REF]Neopterygii Regan, 1923 Pycnodontiformes [START_REF] Berg | A classification of fish-like vertebrates[END_REF]?Coccodontidae Berg, 1940Cosmodus Sauvage, 1879 Type and only species. Gyrodus carentonensis Coquand, 1859. Diagnosis. Large-sized pycnodont fish genus that differs from all other pycnodont genera in having the following combination of characters: elongated, narrow vomerine dentition with three rows of seven or eight subtriangular teeth; teeth of the medial row of the vomer slightly smaller than corresponding adjacent lateral teeth; robust prearticular bone bearing three rows (one main row located medially and two secondary rows located laterally) of large curved drop-shaped teeth (main row) and smaller suboval to subrectangular teeth (secondary rows); complex tooth ornamentation, with a sculpted crown surface (central depression present in all teeth except teeth of the prearticular main row) showing a rugose texture and irregular wrinkles arranged in a more or less pronounced radiating pattern.

Cosmodus carentonensis [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF] Figs

. 1, 3-5A M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 9 1893
), a fragmentary right prearticular dentition from Halling, Kent, England (Fig. 4B); MHNLM 2013.0.2.21, a subcomplete left prearticular dentition from Coulaines, Sarthe department, France (Fig. 4C); APVSM unnumbered specimen, a subcomplete right prearticular dentition from Rouen, Seine-Maritime department, France (Fig. 4D); MGM-2504C, a subcomplete right prearticular dentition from Tiroco, Asturias, Spain (Fig. 4E); MCNA (registration number pending), a fragmentary right prearticular dentition from Sóbron, Álava, Spain (Fig. 4F); MHNLR 2017.10.5, a left dentary (or left premaxilla?) from Nersac ("Le Pas" quarry), Charente department, France (Fig. 3J,K).

Type locality and horizon. "Le Puits des Insurgés", île Madame, Port-des-Barques, Charente-Maritime department, France. Lower upper Cenomanian lithological units C4 and D (Calycoceras guerangeri Zone), "Argiles tégulines de Coquand" Formation [START_REF] Moreau | Analyse de la transgression cénomanienne sur la bordure nord-occidentale du Bassin de l'Aquitaine[END_REF][START_REF] Néraudeau | Variation in echinoid biodiversity during the Cenomanian-early Turonian transgressive episode in Charentes (France)[END_REF][START_REF] Andrieu | The Mid-Cenomanian Event in shallow marine environments: Influence on carbonate producers and depositional sequences (northern Aquitaine Basin, France)[END_REF].

Diagnosis. Same as for genus.

Description

The vomer is an elongate, relatively narrow bone. MHNLR 2017.10.1 (Fig. 3A,B The prearticular corresponds to a massive, well-ossified bone. MHNLR 2017.10.2 (Fig. 3F-H) is a large, complete left prearticular with a well-preserved dentition showing three tooth rows. The main row has nine curved drop-shaped teeth that are devoid of central depression. The largest teeth are 20 mm in width. Nine and eight teeth are preserved in the inner and outer lateral rows, respectively. However, there were originally ten teeth in each of the two lateral rows, as indicated by empty tooth spaces. The lateral row teeth show a suboval to subrectangular contour and display an ornamentation similar to that of vomerine teeth (i.e., central depression, rugose texture and irregular wrinkles showing a more or less pronounced radiating pattern). The symphysis is thin and long. There is a relatively narrow edentulous area between the main tooth row and the symphysis, corresponding to a medioventral lamina.

In cross-sectional view, this lamina is rather thin and concave dorsally. The coronoid process is thick, rather low, and shows a slightly convex dorsal margin. The ventrolateral surface of the prearticular shows a salient coronoid ridge. A large foramen is present laterally, just below the third anterior tooth of the outer lateral row. MHNLR 2017.10.3 (Fig. 3I) is a complete right prearticular belonging to a juvenile. Six teeth are preserved in the main row. The tooth arrangement and tooth morphology are rather similar to those observed in larger specimens, indicating that ontogenetic heterodonty in Cosmodus was very weak. The two main differences with adult dentitions are 1) the proportionally larger size of posterior teeth of

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11 lateral rows and 2) the higher angle between medial and lateral margins of the dentition. In addition, anterior teeth of the two lateral rows are fused in MHNLR 2017. 10.3. MHNLR 2017.10.5 (Fig. 3J,K) is a small subtriangular, flattened bone bearing two incisiform prehensile teeth. This element, interpreted as a left dentary (or, alternatively, a right premaxilla), is tentatively assigned to Cosmodus because of the presence of unusual ornamentation on the tooth crowns. Both teeth are wider than high and not strongly compressed labiolingually. The lingual faces are irregularly wrinkled and show a basal bulge, whereas the labial faces are smooth.

All the Cosmodus specimens previously described from the Anglo-Paris Basin [START_REF] Passy | Description géologique du département de la Seine-Inférieure[END_REF]Sauvage, 1879;[START_REF] Woodward | Some Cretaceous pycnodont fishes[END_REF]Vullo, 2015) and northern Spain [START_REF] Almela | Investigación del Hullero bajo los terrenos mesozoicos de la Costa Cantábrica (zona de Oviedo-Gijón-Villaviciosa-Infiesto). Empresa Nacional[END_REF]Vullo et al., 2009) correspond to large prearticular dentitions (Fig. 4A-E). They are less complete than MHNLR 2017.10.2, all lacking the anterior portion of the dentition. However, they clearly show the same tooth arrangement and morphological features that the material from Charentes, displaying a main row with drop-shaped teeth and two secondary rows with smaller suboval to subrectangular teeth ornamented by irregular radiating wrinkles. The new Spanish specimen from Sóbron is a smaller fragment corresponding to the anterior portion of a right prearticular dentition (Fig. 4F). It is also morphologically consistent with the Charentes material.

Discussion

Synonymy and designation of a neotype

In his synopsis of the Cretaceous fossils of southwestern France ("Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la

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France"), [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF] provided a brief description without illustration of a new species of pycnodont fish, Gyrodus carentonensis, from the upper Cenomanian of the Angoulême area, Charente department. Coquand's original description of Gyrodus carentonensis was based on a single fragmentary vomer (now lost) bearing six teeth characterized by a peculiar, complex ornamentation (Fig. 1). Later, Sauvage (1879[START_REF] Sauvage | Notes sur les poissons fossiles (suite)[END_REF] figured this specimen (Fig. 1), discussed the affinities of this species, found that it was clearly distinct from the other species of Gyrodus, and finally concluded that it should be assigned to a new genus. Thus, Sauvage (1879) erected the genus Cosmodus, in which he also placed a new species, Cosmodus grandis, from the Cenomanian of Seignelay, Yonne department, northeastern France (Fig. 4A). Sauvage (1879[START_REF] Sauvage | Notes sur les poissons fossiles (suite)[END_REF] [START_REF] Cornuel | Description de débris de poissons fossiles provenant principalement du calcaire néocomien du département de la Haute-Marne[END_REF][START_REF] Cornuel | Note sur de nouveaux débris de pycnodontes portlandiens et néocomiens de l'est du bassin de Paris[END_REF] in his new genus Cosmodus, but these two species must be assigned to the genus Gyrodus [START_REF] Woodward | Catalogue of Fossil Fishes in the British Museum (Natural History) -Part III. Containing the Actinopterygian Teleostomi of the Orders Chondrostei (concluded), Protospondyli, Aetheospondyli, and Isospondyli)[END_REF]. The type specimens of Gyrodus imitator and Gyrodus sculptus are prearticular dentitions which display the same features that those of Gyrodus sp. described from the Lower Cretaceous of Germany [START_REF] Kriwet | New insight into the distribution and palaeobiology of the pycnodont fish Gyrodus[END_REF]. Because neither Gyrodus imitator nor Gyrodus sculptus displays diagnostic features, these two species must be considered as nomina dubia and the type material is here referred to Gyrodus sp. [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF]. In the present study, we select the complete vomerine dentition MHNLR 2017.10.1 from the "Argiles tégulines de Coquand" Formation of the Charentes region (type horizon and area) as the neotype of Cosmodus carentonensis, consistently with the type specimen originally described by [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF]. In addition, the complete prearticular dentition MHNLR 2017.10.2, collected from the same locality that yielded the neotype (i.e., "Le Puits des Insurgés", île Madame), is designated as paraneotype.

A prearticular dentition from the middle-upper Cenomanian of the côte Sainte-Catherine in Rouen (Normandy, northwestern France), originally figured by Passy (1832: pl. 15, fig. 1) as "appareil dentaire de poisson" [dental apparatus of fish] and recently referred to Coelodus fimbriatus by [START_REF] Brignon | Les débuts de la paléontologie en Normandie et dans le Boulonnais[END_REF], can be confidently assigned to Cosmodus carentonensis (Fig. 4D).

Comparisons and affinities

The genus Cosmodus shares some dental features with a few other pycnodont genera.

Several authors have considered the genus Cosmodus as a subjective junior synonym of the genus Coelodus [START_REF] Woodward | Catalogue of Fossil Fishes in the British Museum (Natural History) -Part III. Containing the Actinopterygian Teleostomi of the Orders Chondrostei (concluded), Protospondyli, Aetheospondyli, and Isospondyli)[END_REF][START_REF] Woodward | The fossil fishes of the English Chalk -Part V[END_REF][START_REF] Woodward | The fossil fishes of the English Wealden and Purbeck formations -Part II[END_REF][START_REF] Priem | Etude des poissons fossiles du Bassin parisien[END_REF][START_REF] Priem | Sur un pycnodonte du Sénonien supérieur de Tunisie[END_REF][START_REF] Priem | Sur des poissons des terrains secondaires du Sud de la France[END_REF][START_REF] Kriwet | New insight into the distribution and palaeobiology of the pycnodont fish Gyrodus[END_REF]. Woodward (1895: 257) even proposed the replacement name Coelodus major for Coelodus grandis (Sauvage, 1879), which consequently became a junior homonym of Coelodus grandis (Costa, 1856). Like Cosmodus, Coelodus typically has three prearticular tooth rows [START_REF] Woodward | The fossil fishes of the English Chalk -Part V[END_REF][START_REF] Schultz | Der Nachweis von Coelodus (Osteichthyes, Pycnodontidae) im Turonien (Oberkreide) von Gams bei Hieflau, Steiermark, Österreich, und aus der Oberkreide von Kroatien und Italien[END_REF][START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF][START_REF] Szabó | Late Cretaceous (Santonian) pycnodontid (Actinopterygii, Pycnodontidae) remains from the freshwater deposits of the Csehbánya Formation, (Iharkút, Bakony Mountains, Hungary)[END_REF]. However, Cosmodus clearly differs from Coelodus by the tooth shape, the tooth ornamentation, and the number of vomerine tooth rows [START_REF] Woodward | The fossil fishes of the English Chalk -Part V[END_REF][START_REF] Schultz | Der Nachweis von Coelodus (Osteichthyes, Pycnodontidae) im Turonien (Oberkreide) von Gams bei Hieflau, Steiermark, Österreich, und aus der Oberkreide von Kroatien und Italien[END_REF][START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF] (Table 1). As in Cosmodus, the prearticular of the genus Anomoeodus also shows a main tooth row with comma-shaped crowns.

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14 However, the vomerine and prearticular dentitions of Anomoeodus display more tooth rows than those of Cosmodus. In addition, the teeth of Anomoeodus are generally smooth or less ornamented than those of Cosmodus [START_REF] Kriwet | Pycnodont fishes (Neopterygii, †Pycnodontiformes) from the Lower Cretaceous of Uña (E-Spain) with comments on branchial teeth in pycnodontid fishes[END_REF][START_REF] Kriwet | Anomoeodus pauciseriale n. sp. (Neopterygii, Pycnodontiformes) from the White Chalk Formation (Upper Cretaceous) of Sussex, South England[END_REF][START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF][START_REF] Friedman | Ray-finned fishes (Osteichthyes, Actinopterygii) from the type Maastrichtian, the Netherlands and Belgium[END_REF] (Table 1). As Cosmodus, the much smaller coccodontid (sensu lato) genera (Table 1). In Ichthyoceros, there are three prearticular tooth rows as in Cosmodus, but the two secondary rows are located medially and laterally to the main row (Poyato-Ariza and Wenz, 2002: fig. 23a). The presence of three tooth rows in both the vomerine and prearticular dentitions is known in several other pycnodontiform taxa (e.g., Arcodonichthys, Paramicrodon, Phacodus, Proscinetes, Neoproscinetes), but the teeth of the main vomerine tooth row are never triangular in contour and are always larger and wider that those of lateral rows [START_REF] Thurmond | Lower vertebrate faunas of the Trinity Division in North-Central Texas[END_REF][START_REF] Hooks | Synonymy of the pycnodont Phacodus punctatus Dixon, 1850, and its occurrence in the Late Cretaceous of the southeastern United States[END_REF][START_REF] Poyato-Ariza | Marine actinopterygian fauna from the Upper Cretaceous of Albaina (Laño quarry, northern Spain)[END_REF][START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF][START_REF] Poyato-Ariza | New pycnodont fish (Arcodonichthys pasiegae gen. et sp. nov.) from the Early Cretaceous of the Basque-Cantabrian Basin, northern Spain[END_REF]. Lastly, it is worth noting that a rugose tooth crown ornamentation rather similar to that of Cosmodus is convergently present in the large Eocene species Pycnodus mokattamensis, an otherwise distinct pycnodont with five vomerine tooth rows and suboval teeth [START_REF] Priem | Sur les poissons de l'Eocène du Mont Mokattam (Egypte)[END_REF][START_REF] Priem | Sur des poissons fossiles éocènes d'Egypte et de Roumanie et rectification relative à Pseudolates Heberti Gervais sp[END_REF]. The new material described here confirms the validity of the genus Cosmodus, which can be clearly distinguished from Coelodus and other pycnodontiforms by its unique combination of characters.

As Cosmodus is known only by isolated dentitions, caution is needed when attempting to determine the systematic affinities of this genus. However, unusual dental features of [START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF][START_REF] Martín-Abad | Historical patterns of distribution in pycnodontiform and amiiform fishes in the context of moving plates[END_REF][START_REF] Taverne | Ostéologie et phylogénie des Coccodontidae, une famille remarquable de poissons Pycnodontiformes du Crétacé supérieur marin du Liban, avec la description de deux nouveaux genres[END_REF]. In addition, Cosmodus shares with Coccodus a suite of characters, including the number and relative width of vomerine tooth rows (three rows of subequal widths), the slenderness of the vomer (high length/width ratio), the tooth crown ornamentation (e.g., vomerine teeth with wrinkled central depression and peripheral bulges), the morphology of main prearticular teeth (curved drop-shaped contour), and the number of teeth in main rows of vomerine and prearticular dentitions (less than 10) [START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF][START_REF] Kriwet | A comprehensive study of the skull and dentition of pycnodont fishes[END_REF][START_REF] Taverne | Ostéologie et phylogénie des Coccodontidae, une famille remarquable de poissons Pycnodontiformes du Crétacé supérieur marin du Liban, avec la description de deux nouveaux genres[END_REF]) (Fig. 5). As far it is known, Cosmodus mainly differs from Coccodus by its much larger size, its more marked tooth crown ornamentation, and the presence of an additional lateral tooth row in the prearticular dentition. In conclusion, dental features of Cosmodus indicate that this genus is more closely related to Coccodus than to any other pycnodontiform genus, and Cosmodus is therefore tentatively referred to the Coccodontidae.

Distribution and palaeoecology

Outside the Aquitaine Basin, where the type area is located [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF][START_REF] Sauvage | Notes sur les poissons fossiles (suite)[END_REF]Vullo, 2007), the genus Cosmodus is known from the Anglo-Paris Basin [START_REF] Passy | Description géologique du département de la Seine-Inférieure[END_REF]Sauvage, 1879;[START_REF] Woodward | Some Cretaceous pycnodont fishes[END_REF]Vullo, 2015) and from the Asturian Central Depression in the northern margin of the Iberian Peninsula [START_REF] Almela | Investigación del Hullero bajo los terrenos mesozoicos de la Costa Cantábrica (zona de Oviedo-Gijón-Villaviciosa-Infiesto). Empresa Nacional[END_REF]Vullo et al., 2009) (Fig. 6). An additional Spanish occurrence is reported here, based on a previously unpublished specimen coming from the upper Cenomanian of Sóbron (Álava, Basque Country) in the Basque-Cantabrian Basin (Fig. 6). Lastly, a single tooth from the upper Cenomanian (Metoicoceras geslinianum Zone; Dölzschen Formation) of Plauen (Saxony, eastern

M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 16
Germany), originally described as "Gyrodus Münsteri", shows a suboval contour, a central depression and short radiating wrinkles [START_REF] Fischer | Die Fischreste aus dem Plänerschichten von Plauen, Strehlen, Weinböhla und Grosssedlitz[END_REF][START_REF] Licht | Late Cretaceous pycnodont fishes (Actinopterygii, Neopterygii) from Saxony (Eastern Germany)[END_REF]. This specimen, about 6 mm in largest diameter and likely corresponding to an anterior tooth of a prearticular lateral row, may be referred to Cosmodus. However, this assignment, based on Fischer's original figure (Fischer, 1856: fig. 21), must be considered as highly tentative.

Cosmodus therefore appears to be well distributed in Western Europe, from chalky facies with boreal influences (as observed in Kent, Seine-Maritime and Yonne; e.g., [START_REF] Lasseur | A relative water-depth model for the Normandy Chalk (Cenomanian-Middle Coniacian, Paris Basin, France) based on facies patterns of metre-scale cycles[END_REF] to more detrital facies with Tethyan influences (as observed in Charentes, Sarthe, Basque Country and Asturias; e.g., [START_REF] Moreau | Analyse de la transgression cénomanienne sur la bordure nord-occidentale du Bassin de l'Aquitaine[END_REF] (Fig. 6). This indicates that Cosmodus probably lived in a wide range of habitats, from shallow marine to deeper outer shelf environments. However, the material from Charentes, which is abundant, well-preserved and comes from both juvenile and adult individuals, suggests that Cosmodus preferentially inhabited shallow coastal areas such as lagoons and bays. In the type area, Cosmodus cooccurs with other medium-sized to large-sized pycnodont taxa, such as Coelodus, Anomoeodus, Phacodus, and cf. Neoproscinetes [START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF](Coquand, , 1860a, b;, b;R. Vullo, pers. obs.). However, the latter are somewhat smaller and Cosmodus corresponds to the largest form of the Charentes pycnodont assemblage, as also observed in the Anglo-Paris Basin and Asturias (Vullo et al., 2009;Vullo, 2015;[START_REF] Friedman | The English Chalk and London Clay: two remarkable British bony fish Lagerstätten[END_REF]. Mid-Cretaceous pycnodont fishes include some particularly large forms, as exemplified by Coelodus ellipticus and Coelodus gyrodoides from the Albian of southern England [START_REF] Egerton | On some new pycnodonts[END_REF]. With an estimated maximum standard length of about 80 cm (according to the correlation existing between prearticular length and standard length; see [START_REF] Licht | The relationship of prearticular length and standard length in pycnodontiform fishes[END_REF] and an inferred total length of around one meter, the putative coccodontid Cosmodus carentonensis is one of these largesized pycnodonts that flourished during the mid-Cretaceous and strongly contrasts with the small-sized Lebanese coccodontid taxa (around 10 cm in total length for Coccodus; Taverne

M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT

and Capasso, 2014). The observed distribution of Cosmodus in Western Europe can be partly correlated with the middle-late Cenomanian development of oysters such as the gryphaeid species Pycnodonte biauriculata (Pycnodonte Event; [START_REF] Dhondt | The unusual Cenomanian oyster Pycnodonte biauriculatum[END_REF]Videt, 2004;[START_REF] Wilmsen | The middle-upper Cenomanian of Zilly (Sachsen-Anhalt, northern Germany) with remarks on the Pycnodonte Event[END_REF]. These abundant, robust bivalves may have represented a major food resource for such powerful-jawed fishes with a grinding dentition.

If correct, the familial assignment of Cosmodus proposed here considerably extends the palaeogeographic range of the Coccodontidae, a group so far considered endemic to Lebanon [START_REF] Cavin | Palaeobiogeography of Cretaceous bony fishes (Actinistia, Dipnoi and Actinopterygii)[END_REF][START_REF] Martín-Abad | Historical patterns of distribution in pycnodontiform and amiiform fishes in the context of moving plates[END_REF][START_REF] Taverne | Ostéologie et phylogénie des Coccodontidae, une famille remarquable de poissons Pycnodontiformes du Crétacé supérieur marin du Liban, avec la description de deux nouveaux genres[END_REF][START_REF] Marramà | A new species of Gladiopycnodus (Coccodontoidea, Pycnodontomorpha) from the Cretaceous of Lebanon provides new insights about the morphological diversification of pycnodont fishes through time[END_REF]. The presence of a single coccodontid species in Europe would contrast with the relatively high diversity of Lebanese coccodontids (sensu lato), usually regarded as the result of a local radiation event due to peculiar ecological conditions [START_REF] Cavin | Palaeobiogeography of Cretaceous bony fishes (Actinistia, Dipnoi and Actinopterygii)[END_REF][START_REF] Marramà | A new species of Gladiopycnodus (Coccodontoidea, Pycnodontomorpha) from the Cretaceous of Lebanon provides new insights about the morphological diversification of pycnodont fishes through time[END_REF]. In addition, this would support the hypothesis that collecting and taphonomic biases (i.e., "Lagerstätten effect") may be responsible for the so far observed geographic restriction of this peculiar lineage to the Middle East, as previously suggested by [START_REF] Marramà | A new species of Gladiopycnodus (Coccodontoidea, Pycnodontomorpha) from the Cretaceous of Lebanon provides new insights about the morphological diversification of pycnodont fishes through time[END_REF]. Lebanese coccodontids (sensu lato) mostly come from the lower upper Cenomanian strata of Hâqel and Hjoûla [START_REF] Taverne | Ostéologie et phylogénie des Coccodontidae, une famille remarquable de poissons Pycnodontiformes du Crétacé supérieur marin du Liban, avec la description de deux nouveaux genres[END_REF]. The late Cenomanian age of these two fossil-Lagerstätten was first proposed on the basis of an assemblage of planktonic foraminifera from contiguous deposits [START_REF] Hemleben | Rote Tiden und die oberkretazischen Plattenkalke im Libanon[END_REF] and subsequently confirmed by the occurrence of the ammonite Allocrioceras cf. annulatum, a species occurring in the Metoicoceras geslinianum Zone [START_REF] Wippich | Allocrioceras from the Cenomanian (mid-Cretaceous) of Lebanon and its bearing on the palaeobiological interpretation of heteromorphic ammonites[END_REF].

Coccodontids are also present in the En Nammoûra locality [START_REF] Taverne | Ostéologie et phylogénie des Coccodontidae, une famille remarquable de poissons Pycnodontiformes du Crétacé supérieur marin du Liban, avec la description de deux nouveaux genres[END_REF], which is late middle Cenomanian in age as indicated by associations of benthic foraminifera [START_REF] Vecchia | The Cenomanian (Late Cretaceous) Konservat-Lagerstätte of en Nammoûra (Kesrouâne Province), northern Lebanon[END_REF]. Cosmodus is known from the middle to the upper Cenomanian, occurring from the Acanthoceras jukesbrownei Zone (or possibly the underlying During the latest Cenomanian, Cosmodus apparently became extinct and several equivalent-sized taxa appeared in Europe, North America and Africa during the Turonian.

These taxa include some particularly large species of the widespread pycnodontid genus Coelodus (e.g., [START_REF] Woodward | The fossil fishes of the English Chalk -Part V[END_REF][START_REF] Priem | Sur des pycnodontes et des squales du Crétacé supérieur du bassin de Paris (Turonien, Sénonien, Montien inférieur)[END_REF][START_REF] Schultz | Der Nachweis von Coelodus (Osteichthyes, Pycnodontidae) im Turonien (Oberkreide) von Gams bei Hieflau, Steiermark, Österreich, und aus der Oberkreide von Kroatien und Italien[END_REF], the poorly known pycnodontid genus Acrotemnus (= Macropycnodon) (e.g., [START_REF] Woodward | The fossil fishes of the English Chalk -Part V[END_REF][START_REF] Shimada | A new gigantic pycnodont fish from the Juana Lopez Member of the Upper Cretaceous Mancos Shale of New Mexico, U.S.A[END_REF]Vullo and Courville, 2014), and the bizarre serrasalmimid genus Polygyrodus [START_REF] Vullo | A unique Cretaceous-Paleogene lineage of piranha-jawed pycnodont fishes[END_REF]. It can be assumed that this trend to gigantism in various distinct lineages (reported here for the first time within the Coccodontidae), with some forms exceeding one meter in total length, is one aspect of the explosive early Late Cretaceous diversification observed in pycnodont fishes [START_REF] Marramà | A new species of Gladiopycnodus (Coccodontoidea, Pycnodontomorpha) from the Cretaceous of Lebanon provides new insights about the morphological diversification of pycnodont fishes through time[END_REF]. As early as the Cenomanian, new morphological innovations with obvious defensive functions (e.g., horns, spines, armor) evolved independently in several marine fish lineages (e.g., pycnodonts, acanthomorphs), probably in response to the increased levels of predation characterizing the Mesozoic Marine Revolution [START_REF] Chen | New insights on early evolution of spiny-rayed fishes (Teleostei: Acanthomorpha)[END_REF][START_REF] Marramà | A new species of Gladiopycnodus (Coccodontoidea, Pycnodontomorpha) from the Cretaceous of Lebanon provides new insights about the morphological diversification of pycnodont fishes through time[END_REF]. On the basis of the available material (i.e., isolated dentitions), it is not possible to know whether Cosmodus was a well-armored form like small-sized, spinous coccodontids from Lebanon [START_REF] Taverne | Ostéologie et phylogénie des Coccodontidae, une famille remarquable de poissons Pycnodontiformes du Crétacé supérieur marin du Liban, avec la description de deux nouveaux genres[END_REF].

Nevertheless, it is worth noting that the remarkably large size of some mid-Cretaceous pycnodonts such as Cosmodus may have represented an alternative or additional physical defensive adaptation in ecosystems with increasing predation rates. Cosmodus, as well as other large mid-Cretaceous pycnodonts (i.e., Coelodus, Acrotemnus, Polygyrodus), probably fed on robust hard-shelled organisms and may have been preyed upon by large top predators such as lamniform sharks and marine reptiles. The gigantism observed in these pycnodont taxa can be interpreted as a direct consequence of an important phase of predator-prey escalation in Cretaceous marine ecosystems [START_REF] Walker | Post-Paleozoic patterns in marine predation: Was there a Mesozoic and Cenozoic marine predatory revolution?[END_REF].

Conclusions

Our results confirm the important contribution of diagnostic isolated dentitions to our knowledge of the palaeodiversity, palaeobiogeography and palaeoecology of pycnodontiform fishes (e.g., [START_REF] Kriwet | New insight into the distribution and palaeobiology of the pycnodont fish Gyrodus[END_REF][START_REF] Kriwet | The dentition of the enigmatic pycnodont fish, Athrodon wittei (Fricke, 1876) (Neopterygii, Pycnodontiformes; Late Jurassic; NW Germany)[END_REF][START_REF] Szabó | Late Cretaceous (Santonian) pycnodontid (Actinopterygii, Pycnodontidae) remains from the freshwater deposits of the Csehbánya Formation, (Iharkút, Bakony Mountains, Hungary)[END_REF][START_REF] Stumpf | Early Jurassic diversification of pycnodontiform fishes (Actinopterygii, Neopterygii) after the end-Triassic extinction event: Evidence from a new genus and species, Grimmenodon aureum[END_REF].

  basis of material coming from the type region (Charentes, northern Aquitaine Basin, southwestern France) and from other parts of Western Europe (Anglo-Paris

  Paléontologique de Villers-sur-Mer; MA, Muséum d'Auxerre; MCNA, Museo de Ciencias Naturales de Álava, Vitoria-Gasteiz ; MGM, Museo Geominero, Madrid; MHNLM, Musée Vert, Muséum d'Histoire Naturelle, Le Mans; MHNLR, Muséum d'Histoire Naturelle de La Rochelle; NHMUK, Natural History Museum, London, UK.

  Coelodus fimbriatusWoodward, 1893 (NHMUK PV OR 43090), comes from the Holaster

  ) is a complete vomerine dentition (65 mm in length) showing 21 teeth closely arranged in three well-defined longitudinal rows. Seven teeth are preserved in each row. The posteriormost tooth of the medial row is missing. In cross-sectional view, the three rows are in the same plane. With the exception of the anterior teeth of the medial row with a diamond-shaped contour, all the teeth show a subtriangular contour in occlusal view. The teeth of the medial row alternate with those of the lateral rows. The teeth have a central depression, which is larger and more rugose and wrinkled in the crowns of the lateral rows. The ornamentation shows a more or less pronounced radiating pattern. The teeth of the medial row show a thick to the central depression. MHNLR 2017.10.4 (Fig.3C-E) is a vomer fragment bearing four teeth. The preserved portion corresponds to the posterior part of the vomer. It shows the second posteriormost tooth of the medial row, and the three posteriormost teeth of the left lateral row. In left lateral view, the bone shows a welldeveloped subvertical oral border above the tooth row. In dorsal view, the bulged lateral margin of the lateral teeth can be seen.

  [START_REF] Woodward | Some Cretaceous pycnodont fishes[END_REF] described a new large species of Coelodus, C. fimbriatus, on the basis of an incomplete prearticular dentition from the Lower Chalk of Halling, Kent, southeastern England (Fig.4B). The dental morphology and tooth arrangement of this prearticular dentition clearly indicate that this species belongs to the genus Cosmodus. Both Cosmodus grandis Sauvage, 1879 and Cosmodus fimbriatus[START_REF] Woodward | Some Cretaceous pycnodont fishes[END_REF] are undistinguishable from the type species (known by several vomerine and prearticular dentitions), and these two taxa are therefore regarded here as junior synonyms of Cosmodus

Coccodus

  and Ichthyoceros also have a vomer bearing three rows of subtriangular teeth(Poyato-Ariza and Wenz, 2002: fig. 22d; Fig.5B). However, the prearticular dentition of Coccodus shows only two tooth rows[START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF] Kriwet, 2005: fig. 44)

Cosmodus

  provide clues regarding its familial assignment. Interestingly, Poyato-Ariza and[START_REF] Poyato-Ariza | A new insight into pycnodontiform fishes[END_REF] found that subtriangular vomerine teeth represent an autapomorphic character of the clade Coccodus + Ichthyoceros within the Coccodontidae (sensu lato), a highly small-sized, well-armored pycnodonts so far restricted to the middleupper Cenomanian of Lebanon

  Acanthoceras rhotomagense Zone) to the Calycoceras guerangeri Zone (or possibly theM A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPToverlying Metoicoceras geslinianum Zone). Therefore, Cosmodus shows a restricted stratigraphic distribution that is roughly consistent with that of Lebanese coccodontids.

  that the pycnodont fish Cosmodus, occurring in the mid-Cretaceous (Cenomanian) of Western Europe and previously thought to be a junior synonym of Coelodus, is actually a monospecific genus that can be clearly distinguished from all other taxa. The tooth arrangement and tooth morphology of Cosmodus suggest that this large-sized genus is closely related to Coccodus, a small armored form endemic to Lebanon. Cosmodus is therefore tentatively assigned to the Coccodontidae, a highly specialized family of pycnodonts known so far only from the famous Lagerstätten of Lebanon. This new taxonomic interpretation of Cosmodus would extend the palaeogeographic distribution of coccodontids to the European archipelago. Interestingly, the stratigraphic range of Cosmodus is equivalent to that of Lebanese coccodontids (middle-upper Cenomanian).

Fig. 1 .

 1 Figure captions:

Fig. 2 .

 2 Fig. 2. Map and synthetic section showing the geographic locations and stratigraphic

Fig. 3 .Fig. 4 .

 34 Fig. 3. Cosmodus carentonensis[START_REF] Coquand | Synopsis des animaux et des végétaux fossiles observés dans la formation crétacée du sud-ouest de la France[END_REF] from the type region (Charentes, northern

Fig. 5 .

 5 Fig. 5. Comparison between the vomerine dentitions of Cosmodus and Coccodus. A,

Fig. 6 .

 6 Fig. 6. Middle-late Cenomanian palaeogeographic map showing the distribution of Cosmodus

  also placed the species Pycnodus imitator Cornuel, 1877 and Pycnodus sculptus Cornuel, 1877 (Lower Cretaceous of Wassy, Haute-Marne department, northeastern France;

Acknowledgments

We thank Arnaud Brignon for providing information concerning the whereabouts of the Rouen specimen. We are grateful to Horst Gödicke, Jean-Marie Guégan, Bernard Pierson (Association Paléontologique de Villers-sur-Mer), Damien Gendry (Université de Rennes 1),