灰麝鼩物种复合体的系统演化关系、隐存种与核型多态研究

Asian gray shrew (Crocidura attenuata) is a wide-spread species of Soricomorpha, distributed in Southeast mainland of China and Hainan Island, and its distribution extends to Indo-Chinese Peninsula. Our preliminary studies by molecular and karyotypic data indicate that, in China mainland, Taiwan gray shrew (C. tanakae) is also distributed and taxonomically included in the C. attenuata complex, and this species complex also includes at least one cryptic species. The latest study by Motokawa et al. (2001) raised the Taiwan subspecies C. attenuata tanakae as a distinct species C. tanakae in Taiwan Island by different karyotypes, however, it might be a problem for the multi-karyotypes of these two species because the species complex was not recognized at that time. In this project, we intend to analyze molecular and karyotype data of C. attenuata complex by widely collecting specimens over its distribution areas including the type locality of C. attenuata to study phylogeny, species delimitation, species differentiation, and cryptic species in the C. attenuata complex, associated with the impacts of ancient climate events on historical phylogeny and biogeography. As a preliminary exploration, we will analyze the relationship of multi-karyotype and species differentiation by connecting karyotype data with molecular phylogeny results.

灰麝鼩(Crocidura attenuata)是广泛分布于我国大陆东南部与海南岛的广布性鼩形目物种，并向西南延伸至整个印支半岛。申请人的先期初步研究表明我国大陆的灰麝鼩实际上是一个物种复合体，包含有以前被认为仅在台湾分布且形态学上无明显差异的台湾灰麝鼩(C. tanakae)和至少一个隐存种。申请人利用分子数据分析的初步结论表明近年在大陆采集的标本中含有台湾灰麝鼩，而依据染色体核型将台湾灰麝鼩确立为独立物种的研究报道Motokawa et al. (2001)因未能认识到灰麝鼩物种复合体的存在而对这两个物种的核型多态现象产生认定错误。申请人拟通过在广大区域采集灰麝鼩复合体标本，利用分子与核型研究方法明确灰麝鼩复合体内的物种系统演化关系、物种分类与分化、潜在隐存种以及古气候地质事件在系统演化中的作用，并将核型多态与分子演化结果进行关联分析，以初步探索核型多态与物种分化的关系。

灰麝鼩(Crocidura attenuata)与台湾灰麝鼩(C. tanakae)的物种分类关系与地理分布一直是一个未得到解决的问题。虽然Motokawa et al. (2001)利用染色体核型证实了台湾灰麝鼩是一个独立物种，并认为仅分布于台湾岛；同时上述研究报道表明灰麝鼩具有核型多态现象而台湾灰麝鼩无核型多态现象。本项目的研究结果对以上结论进行了纠正与否定，本项目的研究结果证实：（1）台湾灰麝鼩是一个独立物种，但Motokawa et al. (2001)使用的中国大陆灰麝鼩标本实为当时未知的台湾灰麝鼩，其标本染色体核型为当时未知的中国大陆台湾灰麝鼩核型多态性的一种，并以此与台湾岛的台湾灰麝鼩进行了比较，歪打正着地提出了台湾灰麝鼩的独立种地位（论文已投稿Journal of Mammalogy并已通过审稿被接受，待出版）；（2）台湾灰麝鼩并非仅分布于台湾岛，这一点亦得到了其他学者的证实，本项目的研究结果首次给出了台湾灰麝鼩在中国大陆的广域分布数据并纠正了原来的错误分布数据（已发表）；（3）中国大陆不但同时分布灰麝鼩与台湾灰麝鼩，而且分布范围与数量均为台湾灰麝鼩远远超过灰麝鼩（已发表），提示迄今为止对中国大陆灰麝鼩的研究结果实际上大多数是台湾灰麝鼩；（4）在中国大陆灰麝鼩与台湾灰麝鼩以及一个隐存种形成了物种复合体，本研究继续收集样本资料对其系统演化关系与地理扩散机制进行探究。