Hesperotherium(黄昏兽 )——后期爪兽一新属

HESPEROTHERIUM-A NEW GENUS OF THE LAST CHALICOTHERES

记述了山西天镇早更新世爪兽一新属———Hesperotherium。新属为低冠中等大小的爪兽 ,主要鉴别特征是 :吻部极度缩短 ,门齿、犬齿和第一前臼齿消失 ,前臼齿高度退缩 ,上臼齿宽大于长 ,原尖孤立 ,下臼齿后齿带发育。这是爪兽科最后的代表。中国过去在晚上新世至早更新世地层中发现的Nestoritherium ,很可能都应该归入这个新属。这个属的化石目前仅发现于中国。

Chalicothere remains were only occasionally met in late Pliocene-middle Pleistocene deposits of China. Since they were usually very poorly represented, mostly by single teeth, identification was often highly tentative.?Nevertheless,?they were always identified as belonging to the genus Nestorithe- rium (formerly Circotherium ). The latter was erected by Kaup in 1859 based on Falconer and Cautley's description of anterior parts of skulls and lower jaws from the Siwaliks, India.\;On October 14th, 2000, the author had the opportunity to visit the fossil mammal localities in the Tianzhen County, Shanxi, accompanied by Prof. Wei Qi, who found and excavated these localities during the first years of the 1980s. Fortunately enough, some chalicothere fossils were found during the visit at the Loc. 80045, where typical Nihewan fauna were collected by Wei in 1980～1981. The new find of the chalicothere fossils tumed out particularly important in clarification of the affinity of the Chinese chalicothere material so far referred to Nestoritherium . The new fossils show clearly that they materially differ from the Siwaliks Nestoritherium and deserve to be classified as a new genus, for which the name Hesperotherium is proposed, alluding to the pre-extinction stage of the Chalicotheiidae.