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The Hengduan Mountains, situated in the southeastern Tibetan Plateau, have undergone dramatic geological and climatic changes over the Pleistocene epoch. Several studies have revealed that the mountains served as a refugium during the ice age. The large white-bellied rat Niviventer excelsior is a rodent endemic to the Hengduan Mountains, which makes it an appropriate species for investigating the influence of glacial movements on the genetic structure of mammals. In this study, we sequenced the partial mitochondrial DNA control region from 72 N. excelsior specimens collected from 20 localities. The results revealed very high levels of haplotype diversity (h = 0.947) and nucleotide diversity (pi = 0.101) in this species. No common haplotype was found to be shared in samples from all geographic regions. Demographic analyses suggested that N. excelsior populations had not been subject to either expansion or bottleneck. The phylogenetic relationships among the haplotypes have no correlation with their geographical origins, while topology revealed two major clades. We speculate that the populations of N. excelsior may have been restricted to two separate refugia during the Last Glacial Maximum (0.60-0.17 Mya), with one west and one east of the Shaluli Mountains. Between the two major refugia, there existed a more widely distributed network subrefugia, which conserved genetic variations in N. excelsior. These results indicated that complex topographic configuration in the Hengduan Mountains provided a network of refugia to maintain the high level of genetic diversity in Pleistocene glaciations.

The classification and phylogenetic relationships of the genus Blarinella have been traditionally based on morphologicalcharacteristics, and there have been no studies published about the molecular phylogenetic relationships and biogeographyfor this genus. Here, we reconstructed the phylogenetic relationships of the genus Blarinella based on one nuclear (ApoB)and two mitochondrial (cyt-b, 16S rRNA) genes. Our results supported the monophyly of the genus Blarinella and thevalid species status of Blarinella wardi. Nevertheless, two morphologically defined Blarinella species, B. quadraticaudaand B. griselda, were poorly differentiated by molecular data; B. quadraticauda was found embedded within B. griseldamaking the latter a paraphyletic group. These results indicate that B. quadraticauda might be under a budding speciationscenario or is a restricted geographical subspecies of B. griselda. Phylogeographic analyses suggest that diversificationand speciation of Blarinella might have been promoted by vicariance events associated to the complex topography of Southwest China. Further morphological, genetic and ecological studies are necessary to examine these hypotheses.

Background: Crocidura, the most speciose mammalian genus, occurs across much of Asia, Europe and Africa. The taxonomy of Chinese representatives has been studied primarily based on cursory morphological comparisons and their molecular phylogenetic analyses remain unexplored. In order to understand the phylogeny of this group in China, we estimated the first multilocus phylogeny and conducted species delimitation, including taxon sampling throughout their distribution range. Results: We obtained one mitochondrial gene (cytb) (~1, 134 bp) and three nuclear genes (ApoB, BRCA1, RAG1) (2 , 170 bp) for 132 samples from 57 localities. Molecular analyses identified at least 14 putative species that occur within two major well-supported groups in China. Polyphyletic C. wuchihensis appears to be composed of two putative species. Two subspecies, C. rapax rapax and C. rapax kurodai should be elevated to full species status. A phylogenetic tree based on mitochondrial gene from Asian Crocidura species showed that the C. rapax rapax is embedded within C. attenuata, making the latter a paraphyletic group. Three strongly supported undescribed species (C. sp.1, C. sp.2 and C. sp.3) are revealed from Zada County of Tibet (Western China), Hongjiang County of Hunan Province (Central China) and Dongyang County of Zhejiang Province (Eastern China), Motuo County of Tibet, respectively. The divergence time estimation suggested that China's Crocidura species began to diversify during the late Pliocene (3.66 Ma) and the Early Pleistocene (2.29 Ma), followed by a series of diversifications through the Pleistocene. Conclusions: The cryptic diversity found in this study indicated that the number of species is strongly underestimated under the current taxonomy. We propose that the three undescribed species should be evaluated using extensive taxon sampling and comprehensive morphological and morphometric approaches. Climate change since the late Pliocene and the uplift of the Qinghai-Tibet Plateau may result in the diversification and speciation of China's Crocidura species. In short, the underestimated diversity underlines the need for a taxonomic revision of Chinese Crocidura species.

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