A rhinocerotid (Mammalia, Perissodactyla) from the late Miocene Oiso Formation, Kanagawa Prefecture, Japan

Abstract: We describe a fragmentary tooth of a rhinoceros recovered from the middle unit of the upper Miocene Oiso Formation, Kanagawa Prefecture, Japan. The specimen is characterized by its large tooth size, the slightly constricted protocone, the presence of antecrochet, the well-developed crochet and the absence of the cingulum at the lingual protoloph. These characteristics closely resemble the M1 or M2 of a large teleoceratine rhinoceros, Brachypotherium documented from the Miocene of Eurasia and Africa. The present discovery suggests the extensive distribution of this clade in the late Miocene in Far East Asia as well as a faunal connection of rhinoceroses between the Eurasian continent and Japanese islands during the Miocene.