The genus Apodemus is mainly distributed in the Palaearctic Region and south edge of Oriental, while genus Niviventer is distributed in the Oriental Region. More than one species of the two rodents overlap in the eastern Himalayan and Hengduan Mountains. In this study, we reconstructed the phylogenies of the genus Apodemus and the genus Niviventer to infer their evolutionary history. We also analyzed the phylogeographic patterns of several species in these two genera. Meanwhile, the endemic Chinese species A. draco complex was evaluated in this study basing on the combination of morphometric characters and molecular data. We analyzed 97 specimens of the A. draco complex from 39 localities in the Hengduan Mountains and Yunnan plateau for distinguishing the A. draco complex. 27 morphometric variables of each sample were measured for multivariate analysis. All these 97 samples and 16 of them were examined to reconstruct phylogenetic trees using mitochondrial cyt-b and nuclear IRBP gene respectively. Another 11 species of Apodemus were included in these studies for Apodemus phylogenetic analyses. The results of multivariate analyses, Genetic distance of cyt-b and phylogenetic analyses confirmed that A. ilex is a valid species, but A. orestes is not. The tail length is not a valid diagnostic character for distinguishing A. draco and A. ilex. To assess the genetic diversity and biogeographic patterns of A. draco and A. ilex lineage, we sequenced the cyt-b gene from 93 samples of A. draco that were collected from 16 localities in Sichuan and 298 samples of A. ilex from 63 localities on the Yunnan plateau. The results indicated that the phylogenetic pattern of A. draco and A. ilex was strongly related to the existence of deep River valley systems in the Hengduan Mountains: The Jinsha River seemed to be the geographical barrier for divergence of A. draco and A. ilex in the Late Miocene. A. draco could be divided into eastern and western phylogroups by Dadu River, the eastern phylogroup was divided into three subclades following the strong tectonic uplift of the Qinghai-Tibet plateau and strong cooling climate. The western phylogroup was further divided into eastern and western subclades with the Yalong River as the geographical barrier. A. ilex could be divided into eastern and western clades with the Lancang River as a geographical barrier, the western clade was further divided into eastern and western sub-clades with the Nu River as the boundary. The eastern clade was further divided into three subclades. There was no significant difference between populaitons from Mt. Haba and Mt. Yulong that were separated by the Jinsha River, and this might be related to the damming of Shigu barrier lake in the Pleistocene when Mt. Haba and Mt. Yulong were connected. Population dynamic analyses indicated that lineage divergences and population expansions were strongly affected by climate fluctuation and multiple second contacts occurred to form current distributions. We employed phylogenetic analyses of ~1740 bp mitochondrial and ~1952 bp nuclear genes to reconstruct the phylogeny of Niviventer. The results confirmed the validity of N. bukit and N. huang. N. culturatus and N. coninga are sister species, the same as N. niviventer and N. huang. N. langbiani, N. niviventer and N. bukit were first recorded in China, and there might be existed some potential cryptic species. Phylogenetic analyses combined with molecular clock analyses revealed that the evolutionary history of Niviventer has been strongly affected by geological change and climate fluctuation: species in high elevations moved down during the glacial periods and recolonized during the interglacial periods. We infer that the evolutionary radiation of Niviventer derive from early Pliocene and resulted in the current geographical distribution. It implied that the glacial-interglacial periods stimulated evolution of Niviventer and Niviventer recolonized Taiwan, Hainan and other islands when the islands were connected by land bridges during glacial periods. We examined the phylogeographic patterns of three species of Niviventer in the eastern Himalayas and Hengduan Mountains: We first analysed the phylogeographic pattern of N. confucianus using 192 samples from 61 localities in Sichuan, Yunnan and Guangxi. 192 cyt-b sequences and 127 HVR sequences were employed for analyses. Our results revealed that the lineages of N. confucianus relate to mountain ridges, drainage systems and climate changes. Lineages were more strongly affected by climate fluctuation than topography. Sympatric populations clustered into different lineages and indicated a multi-refugia pattern. In N. fulvescens phylogeographic study, 137 cyt-b sequences and 84 HVR sequences were determined from 137 samples that were collected from the eastern Himalayas, Hengduan Mountains, Hainan, Thailand and Vietnam. Our results confirmed that N. confucianus originated from the Pleistocene. Lineage divergences and population expansions were strongly affected by climate fluctuation in the Pleistocene. Adaptive evolution of N. fulvescens was reflected by a move down to low altitudes and low latitudes. We employed phylogeographic analyses of N. excelsior using 184 samples from 56 localities in the eastern Himalayas and Hengduan Mountains. 145 cyt-b sequences and 184 HVR sequences were analysed. The results showed that the lineages were congruent with different phylogenetic structure: the phylogenetic pattern of N. excelsior was strongly related to a rapid uplift of the Tibetan plateau and “three river” region, especially the cooling climate after the uplift. In summary, the mountains and river valleys promoted the genetic diversity of species in the eastern Himalayas and Hengduan Mountains. The phylogeography of Apodemus and Niviventer was strongly related to the complex geographical topography and climate fluctuation. Animals with different dispersal abilities and different ecological adaptability were varying from their phylogeographic patterns: Apodemus were strongly related to the deep drain systems with dry-hot valley, while Niviventer lineages were more strongly affected by climate fluctuation than drainage systems. Sympatric populations clustered into different lineages indicating a multi-refugia pattern.
修改评论