Jing Meidong, Yu Hon-Tsen, Wu Sheng-Hai, Wang Wen, Zheng Xiaoguang
Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223 Yunnan, China; The Graduate University of the Chinese Academy of Sciences, Beijing 100049, China.
Mol Phylogenet Evol. 2007 Aug;44(2):521-9. doi: 10.1016/j.ympev.2007.04.003. Epub 2007 Apr 21.
Chinese species of the genus Niviventer, predominantly distributed in the southeastern Tibetan Plateau and in Taiwan, are a diverse group and have not yet received a thorough molecular phylogenetic analysis. Here, we reconstructed the phylogenetic relationships of 32 specimens representing nine Chinese species of Niviventer, based on sequences of the complete mitochondrial cytochrome b gene. Maximum parsimony, maximum likelihood and Bayesian analysis resulted in three consistent trees, each supported by high bootstrap values. The results showed that the Niviventer species included here are monophyletic. The nine species were classified into three distinct clades: clade A with Niviventer brahma, N. confucianus, N. coxingi, N. culturatus, N. eha and N. fulvescens; clade B with N. andersoni and N. excelsior; clade C with N. cremoriventer. Our results also suggested that N. culturatus should be a valid species rather than a subspecies of N. confucianus. Divergence times among species were calibrated according to the middle-late Pleistocene (1.2-0.13 Mya) fossil records of N. confucianus. The results demonstrated that the first radiation event of the genus Niviventer occurred in early Pleistocene (about 1.66 Mya), followed by the divergence of clades A and B at about 1.46 Mya. Most of the extant Niviventer species appeared during early to middle Pleistocene (about 1.29-0.67 Mya). These divergence times are coincidental with the last uplift events of the Tibetan Plateau, Kun-Huang movement, Pleistocene glaciations and the vicariant formation of Taiwan Strait. Consequently geographical events and Pleistocene glaciations have played a great role in the diversification of Niviventer.
针毛鼠属的中国物种主要分布在青藏高原东南部和台湾地区，种类多样，尚未接受全面的分子系统发育分析。在此，我们基于线粒体细胞色素b基因的完整序列，重建了代表中国针毛鼠属9个物种的32个标本的系统发育关系。最大简约法、最大似然法和贝叶斯分析得到了三棵一致的树，每棵树都有很高的自展值支持。结果表明，这里所包含的针毛鼠属物种是单系的。这9个物种被分为三个不同的分支：分支A包含婆罗洲针毛鼠、社鼠、针毛鼠、大足鼠、黄毛鼠和黄胸鼠；分支B包含安氏白腹鼠和高山白腹鼠；分支C包含灰腹鼠。我们的结果还表明，大足鼠应该是一个有效物种，而不是社鼠的一个亚种。根据社鼠中更新世晚期（120万-13万年前）的化石记录，对物种间的分歧时间进行了校准。结果表明，针毛鼠属的第一次辐射事件发生在早更新世（约166万年前），随后分支A和B在约146万年前发生分歧。大多数现存的针毛鼠物种出现在早更新世至中更新世（约129万-67万年前）。这些分歧时间与青藏高原的最后一次隆升事件、昆黄运动、更新世冰川作用以及台湾海峡的间断形成相吻合。因此，地理事件和更新世冰川作用在针毛鼠的物种分化中起到了重要作用。
