Craniodental anatomy of the hornless rhinocerotid Chilotherium schlosseri (Mammalia, Perissodactyla) from the Late Miocene of Samos Island, Greece

The fossiliferous sites of Samos Island are of major importance amidst the numerous Turolian localities of Greece, partly because it is the type locality of two hornless rhinocerotids, Chilotherium schlosseri and Eochilotherium samium . For more than a century, the island has been excavated by Greek and international teams, leading to a dispersal of fossils in a plethora of museums around the World. In the present work, the entirety of the craniodental material of Chilotherium schlosseri available in different European and American collections is examined for the first time. Additionally, we compared the material to various Chilotherium species from the Late Miocene of Eurasia. A number of diagnostic characters are herein established for C. schlosseri: the markedly depressed frontal and nasal region, the widely separated parietal crests, the complicated enamel folds and the presence of enamel plications on the permanent upper dentition. In terms of morphology, the species that is phenotypically closest to C. schlosseri appears to be C. orlovi from the Late Miocene of Kazakhstan. Both species seem to be more distantly related to the other Samian chilothere, E. samium.