Palaeocybium undetermined

Cicimurri, David J., Knight, James L. & Ebersole, Jun A., 2022, Early Oligocene (Rupelian) fishes (Chondrichthyes, Osteichthyes) from the Ashley Formation (Cooper Group) of South Carolina, USA, PaleoBios 39 (1), pp. 1-38 : 23

PALAEOCYBIUM SP.

FIG. 9P–R

Type species — Cybium proosti, Storms,1897 ; Eocene ; Belgium and England .

Referred specimens (n=1) —SC2007.36.122.

Description —The tooth is lanceolate in labial/lingual view and higher than wide (antero-posteriorly). The anterior and posterior edges are smooth and have sharp continuous cutting edges. Both edges are convex basally, but they are straight at the upper two-thirds and converge apically ( Fig. 9P ). In anterior/posterior view the tooth is weakly curved lingually ( Fig. 9Q ). The cutting edges roughly divide the tooth into labial and lingual faces of roughly equal convexity ( Fig. 9R ).

Remarks —Although specimen SC2007.36.122 is comparable to non-laniary teeth of Sphyraena spp. in our sample, it differs by being much thicker and having more convex labial and lingual faces (compare Fig. 9R to 9H). Additionally, whereas Sphyraena spp. non-laniary teeth are erect and virtually straight, SC2007.36.122 exhibits a medial curvature. The features observed on SC2007.36.122 match those observed on teeth in a Palaeocybium dentary in the SC collection that was recovered from the Ashley Formation (SC 2016.1.14), and it is therefore referred to this genus.

Figures

Figure 9. Teleost teeth from the Givhans Ferry Member, Ashley Formation (Rupelian), Dorchester County, South Carolina. A, B. Albula sp. tooth, SC2015.29.204 in profile (A) and basal (B) views. C, D. Osteoglossidae indet. tooth, SC2015.29.218 in profile (C) and basal (D) views. E–H. Sphyraena sp. cheek tooth, SC2007.36.120 in close-up showing serrations (E), labial (F), carinal (G), and basal (H) views. I–K. Sphyraena sp. laniary tooth, SC2007.36.190 in labial (I), basal (J), and anterior (K) views. L, M. Paralichthyidae indet. tooth, SC2007.36.259 in labial (L) and distal (M) views. N. Trichiurides cf. T. sagittidens laniary tooth, SC2015.29.185 in profile view. O. Trichiurides cf. T. sagittidens laniary tooth, SC2007.36.210 in profile view. P–R. Palaeocybium sp. tooth, SC2007.36.122 in labial (P), carinal (Q), and basal (R) views. S–U. Scomberomorus sp. tooth, SC2015.29.221 in lingual (S), carinal (T), and basal (U) views. Scale bar=0.4 mm in O; 0.5 mm in C, D, L–N, S–U; 1 mm in A, B, I–K; 3 mm in E–H, P–R.