A primitive species of Chilotherium (Perissodactyla, Rhinocerotidae) from the Late Miocene of the Linxia Basin (Gansu, China)

A skull with its articulated mandible attributed to Chilotherium primigenius sp. nov. from the Late Miocene of the Linxia Basin (Gansu, China), is described. This early Late Miocene species is the earliest and most primitive in the genus Chilotherium. Compared with the other Late Miocene species of Chilotherium, a tentative lineage of C. primigenius→ →C.wimani→ other species of Chilotherium is proposed. A Late Miocene Asian radiation is suggested for this genus, starting from Linxia C. primigenius. The origin and dispersal history of the genus Chilotherium are discussed and correlated with major faunal exchanges. The sequence of the Late Miocene Hipparion fauna in the Linxia Basin, which yields the remains described herein, is also discussed.