Early Pleistocene soricomorphs and lagomorphs from the Xiaochangliang site in the Nihewan Basin, Hebei, Northern China

摘要

This paper systematically describes soricomorph and lagomorph remains collected by a screen-washing procedure from the sediments of the Xiaochangliang site with the age of 1.36 Ma. The soricomorph remains described are assigned to the tribe Soricini in the subfamily Soricinae of the family Soricidae, on the basis of the detailed dental morphology. Among the genera of the tribe known from the Pliocene and Pleistocene of Asia, Sorex has morphological characters well coincident with those of the remains. Owing to their incompletion, the specific determination can not be done, and thus they are assigned merely to Sorex sp. All the lagomorph remains belong to the family Ochotonidae. The family comprises two genera, Ochotona and Ochotonoi-des, in the Pliocene and Pleistocene of China. The remains are easily divided into a smaller and larger forms by their striking difference in size. The dental morphology and size of the smaller form indicate its allocation toOchotona. The smaller form is compared with many species of Ochotona known from the Pliocene and Pleistocene as well as the present day of China, and is assigned to the extinct species, O. youngi. The larger form is, however, assigned merely to Ochotona or Ochotonoides sp., because of its limited specimens with poor preservation.