Hamrabatis Cappetta, 1991

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 : 109-111

Genus Hamrabatis Cappetta, 1991

Type species: Hamrabatis ornata Cappetta, 1991 from the Maastrichtian of Egypt.

Hamrabatis bernardezi sp. nov.

Fig. 5A–C .

1991? Dasyatis sp. ; Landemaine 1991: 35, pl. 15: 8, 9.

2002 Hamrabatis sanchezi ; Bernardez 2002: 313, pls. 55, 56, pl. 57: 1. Unpublished Ph.D.

2005 Hamrabatis sp. ; Vullo et al. 2005: 99, fig. 2.7.

Derivation of the name: Species named after Mr. Enrique Bernardez, who originally recognized and described this new species within his unpublished Ph.D. thesis.

Holotype: Specimen UM FVN 1 .

Paratypes: Specimens UM FVN 2 , UM MTG 1 .

Type locality: Vauban cliff, Fouras, Charente−Maritime.

Type horizon: Lower Cenomanian, subunit B2, lithological level B2ms.

Material.—Two teeth from Font−de−Benon, Archingeay−Les Nouillers, Lower Cenomanian, subunit B1; numerous teeth from Vauban cliff at Fouras, Traslemaine at Champniers and Montagan at Mainxe, Lower Cenomanian, subunit B2; four teeth from l’Amas, Roullet–Saint−Estèphe, Upper Cenomanian, unit D.

Diagnosis and comparisons.—Small species of Hamrabatis characterized by its teeth with a rhombic crown in occlusal view, slightly wider than long. Ornamentation consisting of shallow alveoli located at the periphery of the labial face which is rather convex, with a clear but not sharp transverse keel. Lingual face very angular in profile view, with an almost vertical part, below the lingual margin of the labial face. This small−sized species of Hamrabatis is easily distinguished from the two other species previously described from Maastrichtian deposits ( Hamrabatis ornata Cappetta, 1991 from Egypt, and H. weltoni Case and Cappetta, 1997 from Texas) by its smaller teeth, displaying a crown less elongated mesio−distally and with a more rhombic outline.

Description.—In occlusal view, the holotype (UM FVN 1; Fig. 5A ) has a rhombic crown, slightly elongated mesio−distally. A weak transverse keel is developed. The apex of the crown is worn in this specimen. The ornamentation consists of irregular alveoli located on the margins of the occlusal face. The root is nearly half as wide as the crown. In basal view, the root is marked by a deep groove. Some teeth (UM FVN 2 and UM MTG 1; Fig. 5B, C ) are narrower in occlusal view, with a crown as wide as long. They are dorso−ventrally less compressed.

Remarks.—In his unpublished Ph.D. thesis, Bernardez (2002) recently described a new species of Hamrabatis (“ H. sanchezi ”) from abundant material from the Cenomanian of Asturias (northern Spain). The teeth from the Lower Cenomanian of Charentes are similar to the Spanish form although they show a more pronounced ornamentation on both crown faces. Indeed, the Spanish specimens show an enamel very slightly alveolated only at the level of the labial area of the crown. The small differences between these two populations are maybe the result of a preservational bias, and the creation of a further new taxon would not be justified. The original description of this new Cenomanian species by Bernardez (2002) has not been published and “ Hamrabatis sanchezi ” therefore qualifies as a nomen nudum, so we herein name this taxon. The genus Hamrabatis was originally described from the Maastrichtian of Egypt ( Cappetta, 1991), then reported from the contemporary deposits of Texas ( Case and Cappetta 1997), Syria ( Bardet et al. 2000), and Morocco (Pierre Zennaro personal communication 2003). It also occurs in the Coniacian of Morocco (HC unpublished data). This Cenomanian species of Hamrabatis is distinguished from the Maastrichtian species Hamrabatis ornata and H. weltoni by its smaller and narrower teeth. This new species was previously assigned to a dasyatid by Landemaine (1991) owing to its tooth morphology, but its histologic tooth type (orthodont) indicates that it corresponds to a rajiform.

Rajiformes Family incertae sedis or Family? Sclerorhynchidae Cappetta, 1974

Genus Archingeayia nov.

Type species: Archingeayia sistaci sp. nov.

Derivation of the name: From the name of the type locality of the type species.

Diagnosis and comparisons.—Genus with “ Ptychotrygon − like” minute teeth with a high, triangular, and clearly cuspidate crown in labial (or lingual) view; ornamentation absent or very reduced labially, corresponding generally to a basal marginal ridge; a simple medial vertical labial fold can be developed, bifurcating downward and thus delimiting the apron; one or two pairs of slight vertical lingual folds; relatively strong labio−lingual compression. The root is relatively low, half to third as high as the crown.

Among oral teeth of Sclerorhynchidae , Ptychotrygon sensu scricto and closely related forms, Archingeayia gen. nov. is firstly well differentiated from the “cross−like crown” group bearing a well developed apron ( Dalpiazia Checchia−Rispoli, 1933 , Ischyrhiza Leidy, 1856 , Kiestus Cappetta and Case, 1999 , Onchopristis Stromer, 1917 , Pucapristis Schaeffer, 1963 , Plicatopristis Cappetta, 1991 , Renpetia Werner, 1989 ). It is closer to Baharipristis Werner, 1989 , Biropristis Suarez and Cappetta, 2004 , Borodinopristis Case, 1987 , Celtipristis Kriwet, 1999 , Ctenopristis Arambourg, 1940 , Ganopristis Arambourg, 1935 , Libanopristis Cappetta, 1980b , Micropristis Cappetta, 1980b , Ptychotrygon Jaekel, 1894 , Ptychotrygonoides Landemaine, 1991 , Sclerorhynchus Woodward, 1889 , and Texatrygon Cappetta and Case, 1999 . However, teeth of the species of Ptychotrygon are generally low cusped, well ornamented and not strongly labio−lingually compressed. Ptychotrygonoides , Sclerorhynchus , Ganopristis , Biropristis , and Borodinopristis have a radial labial ornamentation. Celtipristis shows a strong constriction between the crown and the root. Teeth of Libanopristis and Micropristis have a rather similar reduced ornamentation but are both relatively low cusped. Teeth of Texatrygon have either a completely smooth crown or numerous short vertical labial folds. Anterior teeth of Ctenopristis show a more distinct and high cusp. Anterior teeth of Baharipristis have a hooked crown strongly bent labio−lingually.

Figures

Fig. 5. Teeth of the rajiform Hamrabatis Cappetta, 1991 from the Cenomanian of Charentes, SW France. Hamrabatis bernardezi sp. nov., Fouras−Vauban (A, B) and Montagan (C), Lower Cenomanian. A. Holotype, specimen UM FVN 1; in occlusal (A1), basal (A2), and lingual (A3) views. B. Specimen UM FVN 2; in occlusal (B1), lateral (B2), labial (B3), and basal (B4) views. C. Specimen UM MTG 1; in occlusal (C1), and basal (C2) views. C3: enlargement of the root showing the endolithic microborings (ichnotaxon Abeliella riccioides Mägdefrau, 1937) near the crown−root junction.