A preliminary report on the Pliocene rhinoceros from Udunga, Transbaikalia, Russia

Over 500 rhinoceros fossils were collected from Udunga (MN15–16a), Transbaikalia, Russia and housed at the Southern Scientific Center, Rostov-on-Don, Russia. Both qualitative and statistic analyses applied for the fossils indicate that they are composed of a single species. 16 individuals are recognized in the collection. The Udunga rhinoceros is allocated into the tribe Rhinocerotini based on the anteriorly extended articulation between the ulna and the semilunar. Although the ossification of nasal septum is unknown, it can be assigned to Stephanorhinus based on the loss of the functional anterior dentition. In addition to the reduced incisor, the quantitative analyses for the dental and the postcranial materials show the similarities between the Udunga materials and S. megarhinus. The quantitative analyses for the central metapodials strongly suggest that the former species is more closely related to the European species than to the Turkish one. It also implies that the rhinoceroses were migrated to Transbaikal area directly from Europe.