The first Sinomastodon(Gomphotheriidae,Proboscidea) skull from the Quaternary in China

The first Sinomastodon(Gomphotheriidae,Proboscidea) skull of the Early Pleistocene,collected from the Renzidong Cave deposits in Anhui Province,Eastern China,is described here as S.jiangnanensis sp.nov.As the only brevirostrine trilophodont gomphotheriid known from the Old World,Sinomastodon was mainly indigenous to China from the Early Pliocene to the Pleistocene.Compared with a few single Pleistocene teeth previously found in China,S.jiangnanensis sp.nov.is represented by a relatively complete skull,mandible and dentition,which is the first discovery of a Quaternary Sinomastodon skull from China.With a brevirostrine,elephant-like skull,no lower tusks,and simple bunodont and trilophodont intermediate molars,the new species is morphologically distinct from other gomphotheres and should belong to the genus Sinomastodon.The new species is more progressive than S.hanjiangensis and the Pliocene type species S.intermedius in its skull and mandible morphology,but is evidently more primitive than the Pleistocene S.yangziensis in its molar morphology.The faunal analysis suggests that the emergence of S.jiangnanensis sp.nov.in Jiangnan area and its southward migration may have been related to a cooling event at the beginning of the Quaternary in Eastern China.