Description
Original diagnosis after Cappetta, Morrison & Adnet, 2019 [27810]: Lower teeth are labio-lingually flattened and broader than high. The main cusp is sharp, bent distally at an angle of about 45° and higher than the first distal cusplet. In antero-lateral files, the five distal cusplets usually more oblique than the main cusp decrease regularly in height. In posterior file, up to seven distal cusplets decrease regularly in size distally, with the main cusp barely higher than the first distal cusplet. At the base of the mesial cutting edge of the main cusp occur two to four very distinct serrations of variable size and shape, more or less erect, with a convex mesial and a straight distal cutting edge. Root of rectangular outline, with the mesial margin concave, the distal margin straight and oblique and a basal edge practically rectilinear. The lingual bulge is marked with the labial face displaying vertical furrows irregularly disposed. Upper anterior teeth (Figure 11(A1–A2)) have an erect sigmoid cusp devoid of cutting edge on its distal basal half, but with a short distal heel. The thick asymmetrical root has straight and parallel oblique marginal edges and a concave basal edge, also displaying a narrow oblique mesial lobe and a broad and rounded distal one. On another anterior tooth (Figure 11(B)) occurs a sharp and oblique distal cusplet. Lower symphysial tooth (Figure 11(E1–E2)) has a straight triangular central cusp flanked by a pair of triangular very diverging marginal cusplets. Root has a salient lingual protuberance with a regularly rounded basal margin.

Remarks
shark-references Species-ID=15532;
type species of Protoheptranchias Cappetta, Morrison & Adnet, 2019 [27810] by monotypy (Art. 68.3 ICZN);
valid after Cappetta, Morrison & Adnet, 2021 [27810]

References