Cenocarcharias rochebrunei ( Sauvage, 1880 )

Vullo, Romain, Cappetta, Henri & Néraudeau, Didier, 2007, New sharks and rays from the Cenomanian and Turonian of Charentes, France, Acta Palaeontologica Polonica 52 (1), pp. 99-116 : 108

Cenocarcharias rochebrunei ( Sauvage, 1880)

Fig. 4 .

1880 Odontaspis rochebrunei, Sauvage 1880: 457 , pl. 13: 3.

Type locality: L’Amas quarry, Roullet–Saint−Estèphe, Charente.

Type horizon: Upper Cenomanian , unit D, lithological level Dm .

Material.—Three teeth (UM AMA 10–12) from l’Amas, Roullet–Saint−Estèphe, and one tooth from Le Mas, Upper Cenomanian, unit D.

Revised diagnosis.—Odontaspidid with relatively robust, narrow teeth, whose crown displays a strongly folded basal bulge on its labial face, and very reduced ornamentation on lingual face. There is one or two pairs of acutely pointed lateral cusplets, rather linked to the main cusp. The root is rather thick and has a strong lingual protuberance, with a clear groove. This species of Cenocarcharias differs from the only other species of the genus, Cenocarcharias tenuiplicatus ( Cappetta and Case, 1975) , by its larger, more robust, and more strongly folded teeth.

Description.—An anterior tooth (UM AMA 10; Fig. 4A ), 11 mm high, shows a sharp and erect main cusp, relatively narrow and slightly bent distally. The labial face is almost flat whereas the lingual face is convex. The labial face is strongly folded at its base, and the basal ledge is very concave, forming a bulge overhanging the root. The enamel of the lingual face displays a slight granular texture around the root contact. There is one pair of erect marginal cusplets, closely linked to the main cusp. The root shows a strong medio−lingual protuberance bearing a deep groove. A lateral tooth (UM AMA 12; Fig. 4C ) has a main cusp very inclined distally, with two pairs of erect lateral cusplets.

Remarks.—The original description of this species by Sauvage (1880) was based on only three teeth of the same position (anterior teeth), coming from the “argiles tégulines de la tranchée de Pisani” (locality located on the commune of L’Houmeau−Pontouvre, surroundings of Angoulême). These specimens are currently lost but the discovery of a series of teeth coming from the same area enables us to redefine this taxon. The combination of morphological characters suggests that this species should be referred to the genus Cenocarcharias Cappetta and Case, 1999 . It is very similar to Cenocarcharias tenuiplicatus , a species with slenderer teeth never exceeding 7 or 8 mm ( Welton and Farish 1993; Cappetta and Case 1999). However, Cenocarcharias rochebrunei may be distinguished from C. tenuiplicatus by its larger (up to 11.5 mm), more robust teeth and by its relatively narrower anterior teeth, showing a more pronounced ornamentation on the labial bulge, but a less marked ornamentation on the lingual face of the cusp. It is interesting to note that distinctive teeth of C. tenuiplicatus occurs in the Lower Cenomanian of Charentes ( Landemaine 1991; Vullo et al. 2005). A tooth from the Cenomanian of Bahariya ( Egypt), figured by Slaughter and Thurmond (1974: fig. 2j) as Odontaspis sp. could be referred to Cenocarcharias sp.

Figures

Fig. 4. Teeth of the odontaspidid Cenocarcharias Cappetta and Case, 1999 from the Cenomanian of Charentes, SW France. Cenocarcharias rochebrunei (Sauvage, 1880), L’Amas, Upper Cenomanian. A. Neotype, specimen UM AMA 10; in labial (A1), mesial (A2), and lingual (A3) views. B. Specimen UM AMA 11; in labial (B1), distal (B2), and lingual (B3) views. C. Specimen UM AMA 12; in labial (C1), and lingual (C2) views.