Integrative taxonomy of the freshwater worm Rhyacodrilus falciformis s.l. (Clitellata: Naididae), with the description of a new species

The genetic and morphological variation within Rhyacodrilus falciformis Bretscher, 1901 (Clitellata: Naididae) in Europe was explored using an integrative approach, with three unlinked genetic markers [the mitochondrial cytochrome c oxidase subunit I (COI), the nuclear histone 3 (H3) and internal transcribed spacer region (ITS)] combined with morphology, to investigate whether this taxon constitutes a single or several species. Using Automatic Barcode Gap Discovery on the COI data set, the specimens were divided into seven clusters, used as hypothetical species that were further tested with the other data sources. Single-gene trees were estimated for all three markers, using coalescence analysis and they were in many parts incongruent with each other. Only one of the clusters was supported by all trees; it was also morphologically differentiated from the other clusters by the shape of its modified penial chaetae. This group consists of two specimens from the Crotot Cave in south-eastern...

本研究采用整合分类学方法，针对欧洲境内钩形溪蚓（Rhyacodrilus falciformis Bretscher, 1901，隶属于环带纲（Clitellata）颤蚓科（Naididae））的遗传与形态变异展开研究。本次研究选取3个不连锁的遗传标记——线粒体细胞色素c氧化酶亚基I（mitochondrial cytochrome c oxidase subunit I，COI）、核组蛋白3（nuclear histone 3，H3）以及内部转录间隔区（internal transcribed spacer region，ITS），结合形态学数据，以明确该类群究竟属于单一物种还是复合物种群。通过对COI数据集应用自动条形码间隔发现算法，研究人员将所有标本划分为7个聚类单元，将其作为假想物种，并利用其余数据源对这些聚类单元开展进一步验证。针对全部3个标记基因，研究人员采用溯祖分析（coalescence analysis）构建单基因树，结果显示多数分支的拓扑结构彼此存在不一致。仅有1个聚类单元获得所有单基因树的支持，且该类群的特化阴茎刚毛形态与其余聚类单元存在显著差异。该类群仅包含采自欧洲东南部克罗托特洞（Crotot Cave）的2份标本……