Carcharias aff. gracilis ( Davis, 1890 )

Adolfssen, Jan S. & Ward, David J., 2015, Neoselachians from the Danian (early Paleocene) of Denmark, Acta Palaeontologica Polonica 60 (2), pp. 313-338 : 327

Carcharias aff. gracilis ( Davis, 1890)

Fig. 6A–C .

Material.—Five teeth from the Ce of Stevns Kridtbrud (MGUH 298452, MGUH 29853, MGUH 29854, GMV2012- 69, GMV2012-70) and two in from the Br2 of Faxe in a private collection (Alice Rasmussen, Faxe).

Description.—The dentition in Carcharias displays both a monognathic and dignathic heterodonty. The main cusp is prominent and elongate, flanked by a pair of tall acute cusplets, which may or may not be divergent. Both the labial and lingual faces are generally smooth with the exception of the labial crown-root boundary which may carry short, strong folds. A median sulcus is present in the basal part of the crown above the dental band in both anteriors and laterals. In all teeth, the main cusp is interconnected with the cusplets and a continuous cutting edge extends over all cusps. The root is bilobed with short rounded lobes and has a median lingual protuberance divided by a deep nutrient groove.

Remarks.—The type series of C. gracilis ( Davis 1890) are poorly preserved. Siverson (1995) figured better preserved specimens; C. gracilis is, however, still poorly defined. None of the specimens from the Ce and the Br carry lingual folds, which are common in the Moroccan C. whitei ( Arambourg 1952) , and this explains why we cannot assign the collected specimens to this species. Case (1996) depicted several specimens of Carcharias teretidens ( Sylvestrilamia teretidens ) which are similar to the specimens from Denmark. The latter, however, tend to be much smaller than the teeth from New Jersey. There is still disagreement around the fossil species of Carcharias , and especially about the use of the Recent genus Carcharias in the late Mesozoic and early Paleogene. Some Late Cretaceous species have been transferred to Eostriatolamia ( Glickman 1980) , but the whole fossil Odontaspidae is generically more diverse than suggested in the current literature and is in a dire need of revision. Until then, our specimens will be kept within Carcharias sensu lato.

Figures

Fig. 6. Lamniformes from the Danian of Stevns Kridtbrud, Karlstrup kalkgrav, and Faxe kalkbrud. A–C. Carcharias aff. gracilis (Davis, 1890). A. MGUH 29852 (Ce) anterior tooth in labial view. B. MGUH 29853 (Ce) anterior tooth in labial (B) and lingual (B) views. C. MGUH 29854 (Ce) anterior tooth in 1 2 labial (C) and lingual (C) views. D–H. Striatolamia cederstroemi Siverson, 1995. D. OESM-10046-5 (Br2) anterior tooth in labial (D) and lingual (D) 1 2 1 2 views. E. OESM-10046-6 (Br2) anterior tooth in labial (E) and lingual (E) views. F. OESM-10046-18 (Br2) anterior tooth in lateral (F), labial (F), and 1 2 1 2 lingual (F) views. G. OESM-10046-12 (Br2) lateral tooth in labial (G) and lingual (G) views. H. OESM-10046-11 (Br2) lateral tooth in labial (H) and 3 1 2 1 lingual (H) views. I. Odontaspis speyeri Dartevelle and Casier, 1943, OESM-10046-8 (Br2) anterior tooth in labial (I) and lingual (I) views. J–L. Palae2 1 2 ohypotodus aff. bronni (Agassiz, 1843). J. MGUH 29855 (Ce) anterior tooth in labial (J), basal (J), and lateral (J) views. K. MGUH 298457 (Br1) lower 1 2 3 anterior tooth in labial (K ), lingual (K ) views. L. MGUH 29856 (Ce) posterior tooth in labial (L ) and lingual (L ) views.