Numerous assemblages of fossil small mammals have been recovered from the Neogene deposits in China over the last 30 years or so. Nevertheless, some taxa in these faunas are represented by only a small number of isolated teeth from very few localities, and these are often assigned as indeterminate genus or species. Four peculiar taxa of rodents, Sayimys sihongensis, Apeomys asiaticus, Neocometes sp. from the Early Miocene Xiacaowan Formation of Sihong, Jiangsu Province, and Yuneomys pusillus from the Late Miocene Shihuiba Formation of Lufeng, Yunnan Province, are described in detail. Comparison of these specimens with similar materials from Eurasia or North America makes distinction from the known species of related genera possible, and therefore two new species (S. sihongensis, A. asiaticus) are named for the Sihong specimens, although the material is rare. A new eomyid genus Yuneomys, previously published under the name Leptodontomys pusillus, is based on specimens from Lufeng. A. asiaticus and Neocometes sp. represent the first records of the genera Apeomys and Neocometes known from Asia and China, respectively. The occurrence of the Neogene rodents in eastern China improves our knowledge of the spatial distribution of these poorly recorded animals, and contributes to a better understanding of paleobiogeographic relationships in Eurasia. Co-occurrence of the new genus with the bunodont eomyids Plesieomys and Heteroeomys in the Lufeng Fauna seems to indicate a differentiation of eomyid taxa in northern and southern faunas of China, and may reflect ecological partitioning within southeastern Asia during the Miocene.
30多年来，中国新近纪堆积物中发现了大量的小哺乳动物化石，但一些种类的材料很少，而且仅在个别地点出现，在动物群中常以未定属、种记述。详细描述了4种罕见的啮齿动物，其中3种，泗洪豪鼠(Sayimys sihongensis)、亚洲别齿始鼠(Apeomys asiaticus)和新来鼠(未定种) (Neocometes sp.)发现于江苏泗洪早中新世下草湾组，一种，细小云南始鼠(Yuneomys pusillus)产自云南禄丰晚中新世石灰坝组。与欧亚或北美有关材料的比较研究表明，江苏泗洪标本无法归入相关属的任何已知种，因此被确定了两个新种(S. sihongensis和A. asiaticus); 禄丰原归入Leptodontomys pusillus的标本与该属的特征不符，被指定为新属Ynueomys。泗洪的A. asiaticus和Neocometes sp.分别代表该属在亚洲和中国的首次记录；它们与S. sihongensis在亚洲远东地区的出现，增加了我们对这些稀有动物地理分布和欧亚古生物地理关系的知识。禄丰的新属Yuneomys与共生的Plesieomys和Heteroeomys属同为丘齿型始鼠类，可能都属热带或亚热带森林型动物；在禄丰动物群中缺少脊齿型始鼠类，与华北动物群的组成不同，似乎表明华南和华北始鼠动物群在中新世期间已有明显的分异，进而支持这一时期亚洲出现了不同生态区系的设想。