Department of Anthropology, New York University, 25 Waverly Place, New York, NY 10003, USA.
Mol Phylogenet Evol. 2011 Jun;59(3):736-45. doi: 10.1016/j.ympev.2011.03.025. Epub 2011 Apr 3.
In order to enhance our understanding of the evolutionary history of squirrel monkeys (Saimiri spp.), we newly sequenced and analyzed data from seven complete mitochondrial genomes representing six squirrel monkey taxa. While previous studies have lent insights into the taxonomy and phylogeny of the genus, phylogenetic relationships and divergence date estimates among major squirrel monkey clades remain unclear. Using maximum likelihood and Bayesian procedures, we inferred a highly resolved phylogenetic tree with strong support for a sister relationship between Saimiri boliviensis and all other Saimiri, for monophyly of Saimiri oerstedii and Saimiri sciureus sciureus, and for Saimiri sciureus macrodon as the sister lineage to the S. oerstedii/S. s. sciureus clade. We inferred that crown lineages for extant squirrel monkeys diverged around 1.5 million years ago (MYA) in the Pleistocene Epoch, with other major clades diverging between 0.9 and 1.1 MYA. Our results suggest a relatively recent timeline of squirrel monkey evolution and challenge previous conceptions about the diversification of the genus and its expansion into Central America.
为了增进我们对松鼠猴（Saimiri spp.）进化历史的理解，我们新测序并分析了代表六个松鼠猴类群的七个完整线粒体基因组的数据。虽然先前的研究为该属的分类学和系统发育提供了一些线索，但主要松鼠猴分支之间的系统发育关系和分歧日期估计仍然不清楚。我们使用最大似然法和贝叶斯程序推断出一个高度分辨率的系统发育树，该树强烈支持玻利维亚松鼠猴与所有其他松鼠猴之间的姐妹关系，支持奥氏松鼠猴和普通松鼠猴的单系性，以及认为大臼齿松鼠猴是奥氏松鼠猴/普通松鼠猴的姐妹谱系。我们推断，现存松鼠猴的冠群分支大约在 150 万年前（MYA）的更新世分化，而其他主要分支则在 0.9 到 1.1 MYA 之间分化。我们的结果表明松鼠猴的进化时间相对较近，这挑战了先前关于该属多样化及其向中美洲扩张的概念。
