基于核型和分子系统学方法对中国猪尾鼠分类与分布的讨论

猪尾鼠属（Typhlomys）是啮齿类中的孑遗类群，片段化分布于我国南方和越南最北部的山地森林。前期我们基于形态和分子系统学的方法将猪尾鼠属现生类群划分为4个物种。但该分类系统仍存在争议和有待于解决的问题：一方面，有学者对大娄山猪尾鼠等是否应属于种级分类单元抱有疑问；另一方面，秦岭、南岭和广西周边的猪尾鼠种群的分类地位仍未有定论。因此，本研究采用核型分析以及分子系统学分析的方法，对我国猪尾鼠的分类及分布进行进一步梳理。本研究首次报道了中华猪尾鼠和大娄山猪尾鼠的G带核型和Ag-NORs的数目和分布，其中中华猪尾鼠2n=36，核型为14(M, SM) + 20 (A)，XY (SM, A)，Ag-NORs 6个；大娄山猪尾鼠2n=56，核型为2 (SM) + 52 (A)，XX (SM, SM )，Ag-NORs 4个。上述核型与已报道的沙巴猪尾鼠核型（2n=38）存在显著差异，支持上述类群均为独立物种。基于线粒体Cyt b，ND2和COⅠ基因的进化关系分析，秦岭种群应属于大娄山猪尾鼠、南岭种群应属于中华猪尾鼠。而来自红河以东的云南南部的种群以及贵州南部的种群情况复杂，暗示云南、贵州和广西的喀斯特地区可能还存在未知的分类单元。

Taxonomy and distribution of the genus Typhlomys in China based on karyotypic and phylogenetic analyses

Typhlomys is a relict genus of Platacanthomyidae. Typhlomys spp. are mainly distributed in the mountainous forests of southern China and northmost Vietnam. Although four species and one putative new species were recognized in a previous study, their karyotypes remain undetermined. In addition, a revision of taxonomic positions of several geographic populations were not determined. In the current study, we determined the karyotypes of Typhlomys cinereus and Typhlomys daloushanensis for the first time, and conducted molecular phylogenetic analysis to clarify the taxonomy and distribution of Typhlomys spp. in China. The diploid number of chromosomes in T. cinereus is 2n=36, with a karyotype of 14(M, SM) + 20 (A), XY (SM, A), and 6 Ag-NORs. T. daloushanensis has 2n=56, 2 (SM) + 52 (A), XX (SM, SM), and 4 Ag-NORs karyotypes. These karyotypes are distinct from that of T. chapensis (2n=38) from Vietnam and southern Yunnan, supporting the validity of each species. Phylogenetic analysis using three mitochondrial genes (Cyt b, ND2 and COI), suggested the Mts. Qinling and Nanling populations should be assigned to T. daloushanensis and T. cinereus, respectively. In addition, the populations from southern Yunnan and southern Guizhou represent distinct evolutionary lineages, implying unrecognized taxa may exist in the Karst mountains in Guangxi, Guizhou and Yunnan.