Brachaeluridae, Applegate, 1974

Cicimurri, David J., Ebersole, Jun A., Stringer, Gary L., Starnes, James E. & Phillips, George E., 2025, Late Oligocene fishes (Chondrichthyes and Osteichthyes) from the Catahoula Formation in Wayne County, Mississippi, USA, European Journal of Taxonomy 984 (1), pp. 1-131 : 8

Brachaeluridae gen. et sp. indet.

Fig. 3A–C

Material examined

UNITED STATES OF AMERICA – Mississippi • 1 isolated tooth; Catahoula Formation ; SC 2013.28.54 .

Description

This tooth crown measures 2 mm in height and 1.5 mm in width. The crown consists of a tall, rather narrow, triangular main cusp flanked by a single pair of lateral cusplets. The main cusp is conical with indistinct mesial and distal cutting edges ( Fig. 3C ). In labial view, the main cusp is very slightly distally inclined, and in profile view, it is straight and lingually directed. The labial crown foot is expanded basally into a convex protuberance (aka apron), and there is a diminutive, medially located, basally directed protuberance ( Fig. 3A ). The lateral cusplets are conical, well-separated from the main cusp, slightly diverging, and located very low on the crown ( Fig. 3B ). The root is not preserved.

Remarks

Specimen SC 2013.28.54 is the only tooth of its kind available to us, but its symmetrical shape indicates that it represents an anterior tooth file. The specimen is clearly distinct from the teeth of two other orectolobiform sharks occurring in the Catahoula Formation (see below). The conical main cusp, single pair of lateral cusplets located low on the crown, and medial protuberance at the labial crown foot are features occurring on the teeth of Paleogene Brachaeluridae , including Brachaelurus and Eostegostoma (see Cappetta 2012). The labial protuberance of SC 2013.28.54 is not as clearly defined as it is on teeth of the aforementioned taxa, but the dentition of extant Brachaelurus waddi ( Bloch & Schneider, 1801) shows that the protuberance is less distinct on lateral/posterior teeth compared to anterior teeth ( Herman et al. 1992). Additional specimens are necessary to accurately ascertain the identity of this orectolobiform taxon.

Figures

Fig. 3. Brachaeluridae gen. et sp. indet. (A–C), Chiloscyllium sp. (D–G), and Nebrius sp. (H–M), teeth. A–C. SC2013.28.54, Brachaeluridae gen. et sp. indet., anterior tooth. A. Labial view. B. Lingual view. C. Mesial view. D–E. SC2013.28.55, Chiloscyllium sp., anterior tooth. D. Labial view. E. Lingual view. F–G. SC2013.28.57, Chiloscyllium sp., lateral tooth. F. Labial view. G. Lingual view. H–I. MMNS VP- 6966, Nebrius sp., tooth. H. Distal view. I. Labial view. J–M. MMNS VP-12033, Nebrius sp., tooth. J. Mesial view. K. Labial view. L. Lingual view. M. Basal view. Scale bars: A–G = 1 mm; H–M = 3 mm.