Hawkins Melissa T R, Helgen Kristofer M, Maldonado Jesus E, Rockwood Larry L, Tsuchiya Mirian T N, Leonard Jennifer A
Smithsonian Conservation Biology Institute, Center for Conservation and Evolutionary Genetics, National Zoological Park, Washington DC 20008, USA; Division of Mammals, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington DC 20013-7012, USA; Estación Biológica de Doñana (EBD-CSIC), Conservation and Evolutionary Genetics Group, Avda. Americo Vespucio s/n, Sevilla 41092, Spain; George Mason University, Department of Environmental Science and Policy, 4400 University Drive, Fairfax, VA 20030, USA.
Division of Mammals, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington DC 20013-7012, USA.
Mol Phylogenet Evol. 2016 Jan;94(Pt B):752-764. doi: 10.1016/j.ympev.2015.10.023. Epub 2015 Oct 31.
The plain long-nosed squirrels, genus Dremomys, are high elevation species in East and Southeast Asia. Here we present a complete molecular phylogeny for the genus based on nuclear and mitochondrial DNA sequences. Concatenated mitochondrial and nuclear gene trees were constructed to determine the tree topology, and date the tree. All speciation events within the plain-long nosed squirrels (genus Dremomys) were ancient (dated to the Pliocene or Miocene), and averaged older than many speciation events in the related Sunda squirrels, genus Sundasciurus. Within the plain long-nosed squirrels, the most recent interspecific split occurred 2.9 million years ago, older than some splits within Sunda squirrels, which dated to the Pleistocene. Our results demonstrate that the plain long-nosed squirrels are not monophyletic. The single species with a distinct distribution, the Bornean mountain ground squirrel (Dremomys everetti), which is endemic to the high mountains of Borneo, is nested within the Sunda squirrels with high support. This species diverged from its sister taxa in the Sunda squirrels 6.62 million years ago, and other plain long-nosed squirrels over 11 million years ago. Our analyses of morphological traits in these related genera support the re-classification of the Bornean mountain ground squirrel, Dremomys everetti, to the genus Sundasciurus, which changes its name to Sundasciurus everetti. Past inclusion in the plain long-nosed squirrels (Dremomys) reflects convergent evolution between these high elevation species.
长吻松鼠属（Dremomys）的普通长吻松鼠是东亚和东南亚的高海拔物种。在此，我们基于核DNA和线粒体DNA序列给出了该属完整的分子系统发育树。构建了串联的线粒体和核基因树以确定树的拓扑结构并对树进行定年。普通长吻松鼠属（Dremomys）内的所有物种形成事件都很古老（可追溯到上新世或中新世），平均比相关的巽他松鼠属（Sundasciurus）中的许多物种形成事件更古老。在普通长吻松鼠中，最近的种间分裂发生在290万年前，比巽他松鼠属内一些可追溯到更新世的分裂还要古老。我们的结果表明普通长吻松鼠并非单系类群。分布独特的单种——婆罗洲山地地松鼠（Dremomys everetti），它是婆罗洲高山地区的特有物种，在高度支持下嵌套于巽他松鼠属内。该物种在662万年前与其在巽他松鼠属中的姐妹类群分化，与其他普通长吻松鼠的分化则超过1100万年前。我们对这些相关属形态特征的分析支持将婆罗洲山地地松鼠（Dremomys everetti）重新分类到巽他松鼠属（Sundasciurus），其名称也相应变为Sundasciurus everetti。过去将其归入普通长吻松鼠属（Dremomys）反映了这些高海拔物种之间的趋同进化。
