New remains of Sinomastodon yangziensis (Proboscidea, Gomphotheriidae) from Sanhe karst Cave, with discussion on the evolution of Pleistocene Sinomastodon in South China

As a valid genus belonging to the family Gomphotheriidae, Sinomastodon is the unique brevirostrine trilophodont gomphotheriid known from the Old World and was primarily indigenous to China from the Early Pliocene to the Pleistocene. The new bunodont molars from the Sanhe karst Cave in Chongzuo, Guangxi Zhuang Autonomous Region (ZAR), South China have been described as Sinomastodon yanziensis of the middle Early Pleistocene, with associated reliable paleomagnetic dating of 1.2–1.6 Ma. This represents the southernmost distribution of Sinomastodon remains found in China. The diagnosis of S. yanziensis is revised here, the evolution of Pleistocene Sinomastodon in China is divided into three temporal stages, and the evolutionary trends on Early Pleistocene Sinomastodon molars are also summarized. Sinomastodon was once prevalent during the Early Pleistocene in South China and possibly became extinct at the end of the Early Pleistocene. Consequently, the Early Pleistocene fauna from South China is suggested to be named the Gigantopithecus-Sinomastodon fauna, to distinguish it from the typical Middle Pleistocene Ailuropoda-Stegodon fauna (s. s.).