The Amazon and neighboring South American river basins harbor the world's most diverse assemblages of freshwater fishes. One of the most prominent South American fish families is the Serrasalmidae (pacus and piranhas), found in nearly every continental basin. Serrasalmids are keystone ecological taxa, being some of the top riverine predators as well as the primary seed dispersers in the flooded forest. Despite their widespread occurrence and notable ecologies, serrasalmid evolutionary history and systematics are controversial. For example, the sister taxon to serrasalmids is contentious, the relationships of major clades within the family are inconsistent across different methodologies, and half of the extant serrasalmid genera are suggested to be non-monophyletic. We analyzed exon capture to reexamine the evolutionary relationships among 63 (of 99) species across all 16 serrasalmid genera and their nearest outgroups, including multiple individuals per species to account for cryptic lineages. To reconstruct the timeline of serrasalmid diversification, we time-calibrated this phylogeny using two different fossil-calibration schemes to account for uncertainty in taxonomy with respect to fossil teeth. Finally, we analyzed diet evolution across the family and comment on associated changes in dentition, highlighting the ecomorphological diversity within serrasalmids. We document widespread non-monophyly of genera within Myleinae, as well as between Serrasalmus and Pristobrycon, and propose that reliance on traits like teeth to distinguish among genera is confounded by ecological homoplasy, especially among herbivorous and omnivorous taxa. We clarify the relationships among all serrasalmid genera, propose new subfamily affiliations, and support hemiodontids as the sister taxon to Serrasalmidae.

中文翻译：

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Piranhas 和 Pacus（Serrasalmidae）的系统基因组学揭示了饮食趋同性和平行性如何混淆传统的形态分类学

亚马逊河和邻近的南美河流域拥有世界上最多样化的淡水鱼群。南美最著名的鱼类家族之一是锯齿鱼科（食人鱼和食人鱼），几乎在每个大陆盆地都有发现。Serrasalmids 是关键的生态分类群，是一些顶级的河流捕食者，也是洪水森林中的主要种子传播者。尽管它们的广泛存在和显着的生态，serrasalmid 的进化历史和系统学是有争议的。例如，serrasalmids 的姊妹分类群是有争议的，家庭内主要进化枝的关系在不同的方法学中不一致，并且现存的 serrasalmid 属中有一半被认为是非单系的。我们分析了外显子捕获，以重新检查所有 16 个 serrasalmid 属的 63 个（共 99 个）物种及其最近的外群之间的进化关系，包括每个物种的多个个体以解释神秘的谱系。为了重建 serrasalmid 多样化的时间线，我们使用两种不同的化石校准方案对这一系统发育进行了时间校准，以解决化石牙齿分类学的不确定性。最后，我们分析了整个家庭的饮食演变并评论了牙列的相关变化，突出了serrasalmids 内的生态形态多样性。我们记录了 Myleinae 内以及 Serrasalmus 和 Pristobrycon 之间普遍存在的非单一属，并提出依赖牙齿等特征来区分属被生态同质性混淆，特别是在草食性和杂食性分类群中。我们阐明了所有 serrasalmid 属之间的关系，提出了新的亚科隶属关系，并支持 hemiodontids 作为 Serrasalmidae 的姐妹分类单元。