This paper describes a fragment of the left lower jaw of Prognatho?don sp. (CSECh 00.2004.1-64) found in the Lisiy Ovrag locality (Lisiy Ravine) near Shirokiy Karamysh village, Lysogorsky District, Saratov Region, Russian Federation (Late Cretaceous, Middle Campanian, Rybushka Formation). The discovered specimen differs from many known representatives of the Mosasauridae family in its unique morphological elements of the tooth crowns (bicarinate, robust morphology, smooth enamel), allowing it to be classified as a member of the genus Prognathodon. The specimen described in this paper is of great importance for understanding the stratigraphic aspects of the genus Prognathodon.
Sofya Chudakova (Thu,) studied this question.