Description
Original diagnosis after Cicimurri, Ebersole, Stringer, Starnes & Phillips (2025) p. 45-46 [34348]: The teeth of the new Oligocene species are distinguished by the combination of a very wide cusp with respect to crown width (cusp width comprises an average of 51% of total tooth width), a highly convex mesial cutting edge, a convex distal cutting edge, an obtuse distal angle (formed by the intersection of the distal cutting edge and distal heel), and a high distal heel (in lingual view) that is straight to only weakly concave. Of the six fossil species currently recognized, the teeth of the new taxon differ from the teeth of the Neogene Galeocerdo aduncus (Agassiz, 1843) by attaining larger overall sizes, having greater overall crown height and a comparatively smaller but wider cusp, and by having a more obtuse angle between the distal cutting edge and distal heel. Galeocerdo platycuspidatum sp. nov. teeth differ from those of the Neogene Galeocerdo capellini Lawley, 1876 by having a mesio-distally wider cusp, a more convex mesial cutting edge, and a distal angle of 90°. These teeth differ from the Eocene G. clarkensis White, 1956 by having a mesial swelling on the cutting edge (as opposed to being evenly convex), coarser serrations, and a wider distal angle (which is less than 90° in G. clarkensis. Galeocerdo platycuspidatum teeth are superficially similar to those of the Eocene G. eaglesomei White, 1955 but are easily separated by having compound (as opposed to simple) serrations. Finally, Galeocerdo platycuspidatum teeth can be differentiated from those of the Miocene Galeocerdo mayumbensisDartevelle & Casier, 1943 by having a wider cusp, a (generally) more convex mesial cutting edge, and a higher and less concave distal cutting edge.

Remarks
shark-references Species-ID=17560

References