Abstract: The Sihong sciurid fauna, a relatively diverse squirrel assemblage found in Jiangsu, China in 1983, is restudied. On the basis of the updated knowledge of Miocene sciurids, the specimens from the Early Miocene Xiacaowan Formation are reexamined and additional descriptions provided, and definitions of the new genera and species previously established are amended. A new genusHeterotamias is named based on the material previously assigned toEutamias; Shuanggouia formerly placed in Pteromyinae is here considered to be a member of Sciurinae due to its generalized sciurid dental pattern; some specimens previously referred to Shuanggouia lui are now identified with Palaeosciurus on account of their differences from the holotype of the species. Five species,Palaeosciurus jiangi, Heterotamias sihongensis, Plesiosciurus sinensis, Shuanggouia lui and Parapetaurista tenurugosa, are recognized in this restudy. Among them, Parapetaurista shows similarities to the Middle-Late Miocene Miopetaurista in dental pattern, but their systematic relationship remains uncertain. The Sihong squirrels appear to represent a sciurid fauna dominated by chipmunk-like animals and restricted to eastern China. 

摘要： 重新研究了中国发现较早、种类较多的江苏泗洪松鼠化石组合。基于对化石松鼠类的最新知识，这些采自下中新统下草湾组的标本被重新鉴定和补充描述，对原拟定为新属和新种的鉴别特征做了修改。原先指定为Eutamias的属被改名为Heterotamias新属；归入鼯鼠亚科的Shuanggouia属被确定为松鼠亚科；Shuanggouia lui中的一些标本被认为与正模的形态特征不符而被指定为Palaeosciurus属。经重新研究，这一组合被订正为Palaeosciurus jiangi, Heterotamias sihongensis,Plesiosciurus sinensis, Shuanggouia lui和Parapetauristatenurugosa 5种。其中Parapetaurista属与中新世中、晚期的Miopetaurista较相似，但它们的系统关系仍难以确定。研究表明，泗洪松鼠化石组合似乎是一个组成上以类花栗鼠为主、分布局限于中国东部地区的地方性动物群。