Brachypotherium Perimense (Perissodactyla, Rhinocerotidae) From The Miocene Of Nakhon Ratchasima, Northeastern Thailand, With Comments On Fossil Records Of Brachypotherium

The cranio-dental and postcranial remains of the Rhinocerotidae collected from the sand pit no. 8 at Nakhon Ratchasima in northeastern Thailand, are described in this study. The remains show cheek teeth that tend to have flattened buccal walls, bucco-lingually broad molariform premolars with short crochet, and brachypodal limb bones, suggesting that these remains belong to genus Brachypotherium. Compared with Afro-Eurasian Brachypotherium, the remains are identified as a South Asian species, Brachypotherium perimense. The result reveals that B. perimense was distributed in Southeast Asia during the Late Miocene. The fossil records of Brachypotherium in Afro-Eurasia show that the genus Brachypotherium was already present in the Indian Subcontinent by the earliest Miocene. This genus then became widely distributed and diversified in Afro-Eurasia during the late Early Miocene and Middle Miocene. Its diversity seems to have decreased before it became extinct by the end of the Miocene, with only the African species, B. lewisi, surviving.