Abstract
Here, we report well–preserved skulls and postcranial specimens of the subgenus Hippotherium from the Linxia Basin, Gansu, China. Based on morphological comparison, the species of subgenus Hippotherium in China, Hipparion weihoense and Hipparion chiai, should be ascribed to the same species, H. weihoense. The species Hipparion prostylum (later Hipparion aff. brachypus) from Maragheh, Iran should also be ascribed to H. weihoense. Phylogenetic analysis shows the subgenus Hippotherium derived from the North American genus Cormohipparion, and as a basal group of Hipparion in Eurasia, representing the Hipparion Datum. Analysis on locomotive ability indicates that H. weihoense likely lived in an open habitat, whereas other species of subgenus Hippotherium likely lived in closed habitats. This result indicates a palaeoecological pattern in the early Late Miocene in Eurasia: influenced by a series of geological events, aridification of mid–latitude Asia progressed, whereas Europe and North Africa remained relatively humid; as the genus originated from East Asia, Hipparion divided rapidly into different groups with differing functional morphology to occupy diverse niches.
Sexual Dimorphism in Perissodactyl RhinocerotidChilotherium wimanifrom the Late Miocene of the Linxia Basin (Gansu, China)