Background. Sakya Bogachev, 1960 is a genus of geoemydid turtles with unusual scalation of the carapace consisting of 9–10 vertebrals and 8–10 pairs of pleurals. It is known from Neogene localities of Eastern Europe and includes two species: Sakya riabinini (Khosatzky, 1946) (= S. pontica Bogachev, 1960), from the late Miocene (MN13) to early Pleistocene of Eastern Europe (Moldova, Romania, Russia, and Ukraine) and Sakya kolakovskii Chkhikvadze, 1968 from the Pliocene of Abkhazia. Attribution of Melanochelys etuliensis Khosatzky and Redkozubov, 1986 from the early Pliocene of Moldova to Sakya is poorly corroborated. Here we report new material of Sakya from the late Miocene of Russia and Ukraine, which, probably, belongs to one or two new species of this genus and expands its stratigraphic distribution. Methods. We examined new material of Sakya, that includes posterior part of carapace and incomplete plastron from Morskaya 2 locality (MN 13, Rostov Province, Russia), incomplete carapace and plastron from Egorovka locality (MN 12, Odessa Province, Ukraine), and fragmentary shell remains from Fortepianka locality (MN 11, Republic of Adygea, Russia). For comparison we used published data and personal observations on other specimens of Sakya. Results. The specimens from Morskaya 2 and Egorovka are assigned to Sakya based on the presence of increased number of vertebrals and pleurals. Both specimens differ from the described species of Sakya by reduced number of vertebrals (seven in the Morskaya 2 specimen, and five in the Egorovka specimen), and extension of the posteriormost vertebral onto pygal. In addition, they differ from S. riabinini in the presence of eight neurals, longer than wide pleurals, and from S. kolakovskii in the presence of two suprapygals and serrated posterior edge of the carapace. The material from Fortepianka is too fragmentary for detailed comparison, but also differs from S. riabinini in the reduced number of vertebrals. Discussion. The reported material may represent one or two new species of Sakya. The reduced number of vertebrals in these forms probably represents a primitive condition, whereas the extension of the posteriormost vertebral onto the pygal may be a synapomorphy, which unites the new forms. Thus, the Morskaya 2 and Egorovka specimens of Sakya may represent a separate primitive lineage of this genus. In this case, S. kolakovskii and S. riabinini form a more advanced clade with increased number of carapacial scales. These issues as well as phylogenetic position of Sakya within Geoemydidae will be checked by future phylogenetic analysis. The Sakya material from Fortepianka (MN11, late Sarmatian) represents the earliest reliable record of this genus, known previously beginning from MN 12 (Meotic).
Rhagasostoma (Bryozoa) from the Late Cretaceous of Eurasia: taxonomic revision, stratigraphy and palaeobiogeography