Freshwater mussels are a species‐rich group with biodiversity patterns strongly shaped by a life history strategy that includes an obligate parasitic larval stage. In this study, we set out to reconstruct the life history evolution and systematics in a clade of freshwater mussels adapted to parasitizing a molluscivorous host fish. Anchored hybrid enrichment and ancestral character reconstruction revealed a complex pattern of life history evolution with host switching and multiple instances of convergence, including reduction in size of larvae, increased fecundity, and growth during encapsulation. Our phylogenomic analyses also recovered non‐monophyly of taxa exhibiting multiple traits used as the basis for previous taxonomic hypotheses. Taxa with axe‐head shaped glochidia were resolved as paraphyletic, but our results strongly suggest the complex morphology is an adaptation to reduce larval size, with reduction in size further accentuated in taxa previously assigned to Leptodea. To more accurately reflect the evolutionary history of this group, we make multiple systematic changes, including the description of a new genus, Atlanticoncha gen. nov., and the synonymy of the genus Leptodea under Potamilus. Our findings contribute to the growing body of literature showing that cladistic hypotheses based solely on morphological characters, including larval morphology, can be flawed in freshwater mussels.

中文翻译：

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比较系统基因组学揭示了具有寄生幼虫的双壳类进化枝中生活史策略的复杂演变（双壳类：Unionoida：Ambleminae）

淡水贻贝是一个物种丰富的群体，其生物多样性模式受到包括专性寄生幼虫阶段在内的生活史策略的强烈影响。在这项研究中，我们着手重建适应寄生于软体动物宿主鱼的淡水贻贝进化枝的生活史进化和系统学。锚定杂交富集和祖先特征重建揭示了一种复杂的生活史进化模式，伴随宿主转换和多个收敛实例，包括幼虫尺寸减小、繁殖力增加和包裹期间的生长。我们的系统基因组分析还恢复了具有多种特征的非单一分类群，这些特征被用作先前分类学假设的基础。具有斧头形球形的分类群被解析为并系，但我们的研究结果强烈表明，复杂的形态是减少幼虫大小的一种适应，在以前分配给 Leptodea 的分类群中，大小的减少进一步加剧。为了更准确地反映这一群体的进化历史，我们进行了多项系统性更改，包括对新属 Atlanticoncha gen 的描述。nov.，以及 Potamilus 下的 Leptodea 属的同义词。我们的研究结果有助于越来越多的文献表明，仅基于形态特征（包括幼体形态）的分支假设在淡水贻贝中可能存在缺陷。包括一个新属的描述，Atlanticoncha gen。nov.，以及 Potamilus 下的 Leptodea 属的同义词。我们的研究结果有助于越来越多的文献表明，仅基于形态特征（包括幼体形态）的分支假设在淡水贻贝中可能存在缺陷。包括一个新属的描述，Atlanticoncha gen。nov.，以及 Potamilus 下的 Leptodea 属的同义词。我们的研究结果有助于越来越多的文献表明，仅基于形态特征（包括幼体形态）的分支假设在淡水贻贝中可能存在缺陷。