Wu Ruiwen, Liu Xiongjun, Guo Liang, Zhou Chunhua, Ouyang Shan, Wu Xiaoping
School of Life Science Shanxi Normal University Taiyuan China.
School of Life Science Jiaying University Meizhou China.
Ecol Evol. 2022 Jul 13;12(7):e9035. doi: 10.1002/ece3.9035. eCollection 2022 Jul.
Accurate species identification is crucial for developing conservation strategies for freshwater mussels, one of the most imperiled faunas in the world. Traditionally, mussel species description primarily relied on conchological characters. However, shell morphology has great variability, which leads to the complexity of species delimitation. As endemic species to China, was originally described by Heude (1877). and were considered for synonymization of based on shell variants in the early 20th century, which has been long debated due to lack of rigorous molecular analysis. Moreover, great morphological variation caused doubt whether there are cryptic species. In this study, we used a combined phylogenetic and morphometric approach to verify the validity of the synonymization of . The results of molecular species delimitation showed that two molecular operational taxonomic units (MOTUs) were identified in spp., including the lineage and the complex lineage (, , , and ). Phylogenetic analyses revealed that formed a basal monophyletic clade, whose divergence time was relatively recent (4.26 Ma [95% HPD = 1.91-7.22 Ma]), and , , and formed a large polytomy group with very shallow branches. In the previous study, we have demonstrated the validity of . The molecular evidences supported that the complex ( + + ) was a valid species; and were synonyms of . In addition, three morphospecies (, , and ) were aggregated without clear differentiation based on shell morphometric analysis. We confirmed multiple phenotypes in for species identification and presumed that the phenotypic plasticity was a response to specific habitats. This study clarified the diversity and phylogeny of the group, which is a crucial step for developing new conservation and management strategies for this imperiled group.
准确的物种鉴定对于制定淡水贻贝的保护策略至关重要，淡水贻贝是世界上最濒危的动物群之一。传统上，贻贝物种描述主要依赖于贝壳学特征。然而，贝壳形态具有很大的变异性，这导致了物种界定的复杂性。作为中国的特有物种，最初由Heude（1877年）描述。在20世纪初，基于贝壳变异， 和 被认为是 的同物异名，由于缺乏严格的分子分析，这一观点长期存在争议。此外，巨大的形态变异引发了关于是否存在隐存物种的疑问。在本研究中，我们采用系统发育和形态测量相结合的方法来验证 的同物异名的有效性。分子物种界定结果表明，在 属物种中鉴定出两个分子操作分类单元（MOTUs），包括 谱系和复合谱系（ 、 、 和 ）。系统发育分析表明， 形成了一个基部单系类群，其分歧时间相对较近（4.26 Ma [95% HPD = 1.91 - 7.22 Ma]），而 、 和 形成了一个分支非常浅的大复系群。在之前的研究中，我们已经证明了 的有效性。分子证据支持复合种（ + + ）是一个有效物种； 和 是 的同物异名。此外，基于贝壳形态测量分析，三种形态种（ 、 和 ）聚集在一起，没有明显分化。我们确认了 中用于物种鉴定的多种表型，并推测表型可塑性是对特定栖息地的一种反应。本研究阐明了 类群的多样性和系统发育，这是为这个濒危类群制定新的保护和管理策略的关键一步。
