喜马拉雅-横断山区是世界上最重要的生物多样性核心地区之一，该地区丰富的生物多样性的起源一直是生物学家研究的热点。其中包括数量和种类众多的食虫类哺乳动物。
蹼足鼩族（Nectogalini）是欧亚大陆小型食虫类哺乳类中重要的一员，现在主要栖息于东喜马拉雅-横断山区，台湾地区和欧洲。 该族群中的各物种有着多样化的生态适应性，包括树栖，穴居和水栖等。因此是研究哺乳类生态适应以及与之相关的形态和生理进化的极好材料。
蒋学龙研究组成员对蹼足鼩族进行了详细的系统发育和生物地理研究，在系统进化、生理进化和生物历史地理各方面都取得了新的进展。结合系统进化的结果，化石和古气候记录，该研究组详细地论证了全球历史气候变化对蹼足鼩族的分布以及进化的影响：东喜马拉雅－横断山区的蹼足鼩首先从欧洲迁移到亚洲北部地区，由于全球气候的变化，在中新世末上新世初蹼足鼩在该地区发生快速分化。到上新世末、更新世初，随着全球变冷和青藏高原的隆升，欧洲的蹼足鼩大量灭绝，而亚洲的类群则向南迁徙。并在第四纪冰期的影响下最终形成今天的分布格局。此研究为气候环境对小型食虫类的进化的影响提供了可靠的依据，并且为喜马拉雅－横断山区生物多样性的起源提供了线索。另外，本研究还阐明了一些在前人研究中有争议的或者不清楚的发育关系，首次证明了蹼足鼩族对水生生活的多次适应性进化并阐明了长尾鼩属（Episoriculus）的并系问题。该研究成果发表在Molecular Phylogenetics and Evolution。(生物谷Bioon.com)
生物谷推荐原文出处：
Molecular Phylogenetics and Evolution doi:10.1016/j.ympev.2010.03.039
A multi-locus phylogeny of Nectogalini shrews and influences of the paleoclimate on speciation and evolution
Kai Hea, b, Ya-Jie Lia, b, Matthew C. Brandleyc, Liang-Kong Lind, Ying-Xiang Wanga, Ya-Ping Zhanga and Xue-Long Jiang a
a State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
b Graduate School of Chinese Academy of Sciences, Beijing, China
c Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
d Laboratory of Wildlife Ecology, Department of Life Science, Tunghai University, Taichung, Taiwan
Nectogaline shrews are a major component of the small mammalian fauna of Europe and Asia, and are notable for their diverse ecology, including utilization of aquatic habitats. So far, molecular phylogenetic analyses including nectogaline species have been unable to infer a well-resolved, well-supported phylogeny, thus limiting the power of comparative evolutionary and ecological analyses of the group. Here, we employ Bayesian phylogenetic analyses of eight mitochondrial and three nuclear genes to infer the phylogenetic relationships of nectogaline shrews. We subsequently use this phylogeny to assess the genetic diversity within the genus Episoriculus, and determine whether adaptation to aquatic habitats evolved independently multiple times. Moreover, we both analyze the fossil record and employ Bayesian relaxed clock divergence dating analyses of DNA to assess the impact of historical global climate change on the biogeography of Nectogalini. We infer strong support for the polyphyly of the genus Episoriculus. We also find strong evidence that the ability to heavily utilize aquatic habitats evolved independently in both Neomys and Chimarrogale + Nectogale lineages. Our Bayesian molecular divergence analysis suggests that the early history of Nectogalini is characterized by a rapid radiation at the Miocene/Pliocene boundary, thus potentially explaining the lack of resolution at the base of the tree. Finally, we find evidence that nectogalines once inhabited northern latitudes, but the global cooling and desiccating events at the Miocene/Pliocene and Pliocene/Pleistocene boundaries and Pleistocene glaciation resulted in the migration of most Nectogalini lineages to their present day southern distribution.
