甘肃东乡龙担的河狸(啮齿类,哺乳动物)化石——龙担哺乳动物群补充报道之一

BEAVER (RODENTIA, MAMMALIA) FOSSILS FROM LONGDAN,GANSU, CHINA--Addition to the Early Pleistocene Longdan Mammalian Fauna (1)

报道了在甘肃省首次发现的河狸化石:安氏河狸(Castor anderssoni)。安氏河狸在甘肃东乡的发现,扩大了河狸化石在我国的分布范围,并进一步证明龙担地点的黄土的时代为早于2Ma的早更新世。对现生河狸生存环境的对比分析表明,东乡地区在早更新世时可能比现在更湿冷,河、湖广布,树木较多,与现在温带半干旱气候的黄土丘陵地区的气候和环境差别很大。这种差别很可能是青藏高原后期抬升的结果。

Summary In the autumn of 2003 some beaver fossils were collected from Longdan, when the monograph on the Longdan Mammalian Fauna (Qiu et al., 2004) was under press. It is first time to find beaver in Gansu Province. The discovery not only enlarged the list of the Longdan Mammalian Fauna from 31 to 32 taxa, further confirmed the ancientry of the Longdan Fauna, but also expanded the distribution area of the beavers to the Gansu Province also. In addition, the discovery threw some new light on the paleoenvironments of the Longdan area during the early Pleistocene.