Postcranial anatomy of the Late Miocene Eurasian hornless rhinocerotid Chilotherium

Abstract

The hornless rhinocerotid genus Chilotherium is one of the most common rhinoceroses found in Eurasia during the Late Miocene, even being the most abundant large mammal in some localities. Despite its high frequency, much is still unknown about the anatomy and taxonomy of some representatives of the group, because most studies focus solely on cranial and dental remains. For this reason, we describe the postcranial material of the three well-known chilothere species Chilotherium persiae from the Upper Miocene of Maragheh (Iran), Chilotherium habereri from the Upper Miocene of Kutschwan (China), and Chilotherium schlosseri from the Upper Miocene of Samos (Greece). A comparison to postcranial material of other chilotheres from the literature reveals some characters that can assist the identification of some species, such as the morphology and dimensions of the patella and the metapodials, the morphology of the proximal articulation of tibia, and the arrangement of the articular facets for the calcaneum on the astragalus. The comparison supports previous hypotheses about the relationships of some chilotheres that were only based on cranial features, including the plesiomorphic nature of ‘ Chilotherium ’ wimani from the Upper Miocene of China and the close relationship of C. persiae and C. habereri .