Hanson J Delton, Bradley Robert D
Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131 USA,
Occas Pap Tex Tech Univ Mus. 2008 Sep 12;275:1-11.
Nucleotide sequences from the mitochondrial DNA cytochrome-b gene were used to infer phylogenetic relationships and estimate genetic distances from 10 individuals of Melanomys caliginosus and to explore the hypothesis that this taxon is comprised of multiple species. Individuals of four geographic populations of M. caliginosus from Central America (Nicaragua and Costa Rica), Panama, Venezuela, and Ecuador, respectively, were included in this analysis. Topologies obtained from maximum parsimony and Bayesian inference analyses were identical and produced clades referable to each of the geographic populations. Genetic distances between any pair-wise comparisons of the four groups (except between Panamanian and Venezuelan samples) were comparable to values estimated from comparisons of sister species in the closely related genus Nectomys. Distances between samples from Panama and Venezuela were greater than those of samples within the Ecuadorian and Central American clades, but less than that between species of Nectomys. Based on results from the sequence data, it appears that all four of the populations should be elevated to species level; however, additional data are needed to resolve the nomenclature of the Panamanian and Venezuelan populations.
线粒体DNA细胞色素b基因的核苷酸序列被用于推断10只阴暗黑鼠个体之间的系统发育关系并估计遗传距离，以探究该分类单元由多个物种组成这一假说。分别来自中美洲（尼加拉瓜和哥斯达黎加）、巴拿马、委内瑞拉和厄瓜多尔的四个地理种群的阴暗黑鼠个体被纳入该分析。通过最大简约法和贝叶斯推断分析获得的拓扑结构相同，并产生了可归于每个地理种群的分支。四组之间任意两两比较的遗传距离（巴拿马和委内瑞拉样本之间除外）与从近缘属水鼠属姐妹物种比较中估计的值相当。巴拿马和委内瑞拉样本之间的距离大于厄瓜多尔和中美洲分支内样本之间的距离，但小于水鼠属物种之间的距离。基于序列数据的结果，似乎所有四个种群都应提升到物种水平；然而，需要更多数据来解决巴拿马和委内瑞拉种群的命名问题。
