The first described Onchopristis Stromer, 1917, (Elasmobranchii: †Onchopristidae) from the marine Maastrichtian of Dakhla Formation, Western Desert, Egypt

Abstract

An exceptional hypertrophic batoid rostrum of exceptional size (TL = 146 cm) and four fragmentary rostral teeth collected from the marine Maastrichtian of the Dakhla Formation, Egypt. Both the macroscopic aspects (with the presence of a "wood-like" layer that covers the central part of the rostrum and the presence of skin denticles at the bases of the ventral face) and microscopic characters (presence of tessellated cartilage in the central part of the rostrum and of laminated cartilage in the peripheral areas of it) demonstrate that the rostrum belongs to a large specimen of the genus Onchopristis Stromer, 1917. The absence of complete rostral teeth prevents the establishment of a new species. Nonetheless, the described finds demonstrate, for the first time, that the genus Onchopristis persisted in the euryhaline areas of North Africa until the end of the Cretaceous.