The Effectiveness of Molecular, Karyotype and Morphological Methods in the Identification of Morphologically Conservative Sibling Species: An Integrative Taxonomic Case of the Species Complex in Mainland China.

The conservation of morphology has resulted in considerable issues in the taxonomy of small mammals, especially for the identification of sibling species. Moreover, it is often difficult to completely solve such taxonomic problems by relying only on a single research method. The genus is one of the genera with a conservative morphology and high species diversity. Among them, has been considered in the field as the most widely distributed and common species. In fact, it is a species complex containing multiple species, and the classification and distribution of this species is controversial. In this study, the species and distribution of the species complex experienced an integrated revision using three different levels of research methods: molecular, karyotype and morphology. The results show that (1) the species complex contains four known species (, , and ) and a cryptic species distributed in Guangxi, which may be the same undescribed species as the "" distributed in Vietnam. (2) is only distributed around the Sichuan Basin, is the most widely distributed throughout Southern China, and and are almost sympatric in Southeast China. Furthermore, (3) although the molecular method lacks a unified threshold for species classification, it can rapidly and effectively identify the species of the species complex. Although karyotype and morphology methods cannot completely solve the species classification issues in respect of the species complex, they can provide supplemental information for taxonomic purposes. Therefore, the integrated taxonomic method can present the advantages of different methodological levels, and will provide further evidence for the taxonomy of sibling species with a conservative morphology.