A Diverse Assemblage of Species (Elasmobranchii: Ptychodontidae) from the Upper Cretaceous of Ukraine, with Comments on Possible Diversification Drivers During the Cenomanian

New isolated teeth from the Upper Cretaceous of Ukraine and belonging to the extinct durophagous shark are described here. The taxonomic identification of the examined material reveals a quite diverse Cenomanian shark fauna which comprised both cuspidate and un-cuspidate species of from the coastal areas at the north-western margin of the Ukrainian Massif. In addition, from the Turonian of Ukraine is reported here for the first time. The revision of the Ukrainian record of revealed that most specimens described here are the oldest so far known from this part of the European Peri-Tethys. Moreover, the present study highlights the co-occurrence of cuspidate and un-cuspidate and a variety of shelled macroinvertebrates, which inhabited coastal and offshore areas of the European epicontinental seas during the Late Cretaceous. The availability of different prey items is proposed here as one of the possible drivers, in addition to abiotic environmental factors, for the diversification of shark tooth morphologies, and possible trophic partitioning between cuspidate and un-cuspidate species of the genus .