Incisors of primitive rhino found from the Early Miocene of Linxia Basin in Gansu, China
Aprotodon is a large-sized primitive rhinocerotid form, distinguished by relatively robust and strongly curved lower incisors, and the specialized wide mandibular symphysis, which is similar to that of the hippopotamus. It has been reported from the Late Oligocene Jiaozigou Fauna of the Linxia Basin, but the Early Miocene deposits of this basin produced only a few lower cheek teeth. In May 2008, six huge tusk-like incisors of Aprotodon were collected from the Early Miocene Shangzhuang Formation in the Linxia Basin, and Dr. DENG Tao, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, described them in the latest issue of Vertebrata PalAsiatica 2013(2). This find not only showed that Aprotodon survived surely into the Early Miocene in the Linxia Basin, but also proved that the climate in the Linxia Basin during the Early Miocene was similar to that of the Late Oligocene.