Department of Biology, City College of New York, City University of New York, New York, NY 10016, USA; Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History, Central Park West at 79th St., New York, NY 10024, USA.
Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA; J.F. Bell Museum of Natural History, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA.
Mol Phylogenet Evol. 2014 Oct;79:199-214. doi: 10.1016/j.ympev.2014.05.029. Epub 2014 Jun 2.
Short-tailed opossums (genus Monodelphis) represent one of the most speciose clades of New World marsupials, with 26 currently recognized species that collectively range from eastern Panama to northern Argentina. Here we present the first phylogenetic analyses of the genus based on dense taxonomic sampling and multiple genes. From most sampled species we obtained >4800bp of DNA sequence from one mitochondrial gene (CYTB), two autosomal exons (IRBP exon 1, BRCA1 exon 11), one autosomal intron (SLC38 intron 7), and one X-linked intron (OGT intron 14). Maximum-parsimony, maximum-likelihood and Bayesian analyses of these data strongly support the monophyly of Monodelphis and recover six major clades within the genus. Additionally, our analyses support previous suggestions that several nominal taxa are synonyms of other species (M. "sorex" of M. dimidiata, M. "theresa" of M. scalops, M. "rubida" and M. "umbristriata" of M. americana, and M. "maraxina" of M. glirina). By contrast, four unnamed lineages recovered by our analyses may represent new species. Reconstructions of ancestral states of two discrete characters-dorsal pelage color pattern and habitat-suggest that the most recent common ancestor of Monodelphis was uniformly colored (with unpatterned dorsal pelage) and inhabited moist forest. Whereas some dorsal pelage patterns appear to have evolved homoplastically in Monodelphis, dorsal stripes may have had a unique historical origin in this genus.
短尾负鼠（Monodelphis）属是新域有袋类中最具多样性的类群之一，目前共有 26 个被认可的物种，分布范围从巴拿马东部到阿根廷北部。本研究首次基于密集的分类采样和多个基因对该属进行了系统发育分析。从大多数采样物种中，我们获得了来自一个线粒体基因（CYTB）、两个常染色体外显子（IRBP 外显子 1、BRCA1 外显子 11）、一个常染色体内含子（SLC38 内含子 7）和一个 X 连锁内含子（OGT 内含子 14）的超过 4800bp 的 DNA 序列。这些数据的最大简约法、最大似然法和贝叶斯分析均强烈支持短尾负鼠属的单系性，并在该属内恢复了六个主要的分支。此外，我们的分析还支持了先前的一些建议，即几个命名分类单元是其他物种的同义词（M. "sorex"是 M. dimidiata 的同义词，M. "theresa"是 M. scalops 的同义词，M. "rubida"和 M. "umbristriata"是 M. americana 的同义词，M. "maraxina"是 M. glirina 的同义词）。相比之下，我们的分析中恢复的四个未命名谱系可能代表新的物种。两个离散特征——背部皮毛颜色图案和栖息地——的祖先状态重建表明，短尾负鼠属的最近共同祖先具有均匀的颜色（无图案的背部皮毛），并栖息在潮湿的森林中。虽然 Monodelphis 中的一些背部皮毛图案似乎是同源进化而来的，但背部条纹在该属中可能具有独特的历史起源。
