Nebrius, Ruppel, 1837

Cicimurri, David J. & Knight, James L., 2009, Late Oligocene sharks and rays from the Chandler Bridge Formation, Dorchester County, South Carolina, USA, Acta Palaeontologica Polonica 54 (4), pp. 627-647 : 629-630

Nebrius cf. N. serra (Leidy, 1877)

Fig. 3B .

Referred specimen.—SC 2009.18.1.

Comments.—Teeth of extant Nebrius Rüppel, 1837 have more than three pairs of rather small lateral cusplets (our specimen has five pairs), whereas teeth of extant Ginglymostoma Müller and Henle, 1837 have only two or three pairs of robust lateral cusplets ( Compagno 1984; Compagno et al. 2005). We concur with Cappetta (1987) and Purdy et al. (2001) that fossil teeth of Nebrius are sometimes misidentified as Ginglymostoma . Our specimen is morphologically similar to Acrodobatus serra Leidy, 1877 (figs. 10–12) from the “Ashley phosphate beds” of South Carolina. The stratigraphic and temporal occurrence of these fossils is difficult to determine because economically important phosphate deposits occur within Oligo−Miocene units ( Weems and Sanders 1986), and other fossils reportedly from “Ashley phosphate beds” are definitively of Pleistocene age ( Sanders 2002). The species is, in our opinion, referable to Nebrius .

A very similar species, Ginglymostoma delfortriei Daimeries, 1889 , has been reported from the Miocene of France ( Cappetta 1970) and the Oligocene Belgrade Formation of North Carolina ( Müller 1999). Yabumoto and Uyeno (1994) assigned the G. delfortriei morphology to Nebrius . According to Cappetta (1970), N. serra differs from the G. delfortirei morphology in having a longer labial basal protuberance that is more uniformly united with the remainder of the crown foot. If these characteristics are sufficient to separate two species, then our specimen, as well as the Oligocene material reported by Müller (1999), is closer to N. serra . To our knowledge, the only European Oligocene record of Nebrius is from the French Rupelian, and our specimen does not differ appreciably from the material discussed by Génault (1993).

Stratigraphic and geographic range.—Oligocene (Chattian), USA (North and South Carolina).

Figures

Fig. 3. Shark remains from Summerville, upper Chattian. A. Squatina cf. S. angeloides van Beneden, 1873, BCGM 9043, antero−lateral tooth, labial view. B. Nebrius cf. N. serra (Leidy, 1877), SC2009.18.1, antero−lateral tooth, labial view. C. Rhincodon cf. R. typus (Smith, 1828), BCGM 9045, anterior tooth, labial (C1), lateral (C2), and basal (C3) view. D.?Cetorhinus parvus (Leriche, 1908), BCGM 9050, dermal scale, dorsal view, anterior at bottom.