Chen Xin, Jiang Ke, Guo Peng, Huang Song, Rao Dingqi, Ding Li, Takeuchi Hirohiko, Che Jing, Zhang Ya-ping, Myers Edward A, Burbrink Frank T
Department of Biology, The College of Staten Island, The City University of New York, 2800 Victory Blvd., Staten Island, NY 10314, United States; Department of Biology, The Graduate School and University Center, The City University of New York, 365 Fifth Ave., NY, NY 10016, United States.
Mol Phylogenet Evol. 2014 Jan;70:130-6. doi: 10.1016/j.ympev.2013.09.003. Epub 2013 Sep 21.
Delimiting species and clarifying phylogenetic relationships are the main goals of systematics. For species with questionable taxonomic status, species delimitation approaches using multi-species coalescent models with multiple loci are recommended if morphological data are unavailable or unhelpful. Moreover, these methods will also reduce subjectivity based on genetic distance or requirement of monophyletic genetic lineages. We determine the validity and phylogenetic position of a rare and long controversial species of Chinese reptile, the Szechwan ratsnake (Euprepiophis perlaceus), using multi-locus data from multiple individuals and coalescent-based approaches. Species were first delimited using Bayesian Phylogenetics & Phylogeography (BP&P), Brownie and Bayes Factor model comparison approaches, while relationships among species were estimated using species tree inference in (*)BEAST. Results indicate that Euprepiophis perlaceus is a distinct species sister to Euprepiophis mandarinus. Despite gene tree discrepancy, the coalescent model-based approaches used here demonstrate the taxonomic validity and the phylogenetic position of Euprepiophis perlaceus. These approaches objectively test the validity of questionable species diagnoses based on morphological characters and determine their phylogenetic position.
界定物种和厘清系统发育关系是系统分类学的主要目标。对于分类地位存疑的物种，如果形态学数据不可用或无济于事，建议使用基于多基因座的多物种溯祖模型的物种界定方法。此外，这些方法还将减少基于遗传距离或单系遗传谱系要求的主观性。我们使用来自多个个体的多基因座数据和基于溯祖的方法，确定了中国一种珍稀且长期存在争议的爬行动物——四川锦蛇（Euprepiophis perlaceus）的有效性及其系统发育位置。首先使用贝叶斯系统发育与系统地理学（BP&P）、布朗尼方法和贝叶斯因子模型比较方法来界定物种，同时使用（*）BEAST中的物种树推断来估计物种之间的关系。结果表明，四川锦蛇是玉斑锦蛇（Euprepiophis mandarinus）的姐妹物种，是一个独特的物种。尽管基因树存在差异，但这里使用的基于溯祖模型的方法证明了四川锦蛇的分类有效性及其系统发育位置。这些方法客观地检验了基于形态特征的可疑物种诊断的有效性，并确定了它们的系统发育位置。
