Reappraisal of some perissodacyl fossils from the Middle Eocene of the Lijiang Basin, Yunnan, China with a revision of tapiroid Diplolophodon

Abstract: The Lijiang Fauna from the Lijiang Formation of Lijiang, western Yunnan, was dominated by 13 species of perissodactyl fossils, and its age ranged from Irdinmanhan to Sharamurunian Asian Land Mammal Ages (ALMA) according to previous research. Based on reanalysis of some perissodactyls from the Lijiang Fauna, it is suggested here that Rhodopagus yunnanensis is a junior synonym of Lijiangia zhangi, which is similar to Lophiohippus and placed in Anchilophini within the Palaeotheriidae. The enigmatic and scarce Lunania is here regarded as a palaeothere rather than a chalicothere based on its morphological similarities with Paranchilophus, and Lophiohippus probably represents the upper dentitions of Lunania. Furthermore, deperetellid Diplolophodon is revised and comprised of three species: D. similis, D. lunanensis, and D. xiangshanensis (comb. nov.). Teleolophus xiangshanensis from the Lijiang Formation is reassigned to Diplolophodon xiangshanensis. The revised perissodactyls from the Lijiang Fauna are comparable to those from the Rencun Member of the Hedi Formation of the Yuanqu Basin, and its age is confined to Sharamurunian ALMA.