The Neotropics harbor the most species-rich freshwater fish fauna on the planet, but the timing of that exceptional diversification remains unclear. Did the Neotropics accumulate species steadily throughout their long history, or attain their remarkable diversity recently? Biologists have long debated the relative support for these museum and cradle hypotheses, but few phylogenies of megadiverse tropical clades have included sufficient taxa to distinguish between them. We used 1288 ultraconserved element loci spanning 293 species, 211 genera, and 21 families of characoid fishes to reconstruct a new, fossil-calibrated phylogeny and infer the most likely diversification scenario for a clade that includes a third of Neotropical fish diversity. This phylogeny implies paraphyly of the traditional delimitation of Characiformes because it resolves the largely Neotropical Characoidei as the sister lineage of Siluriformes (catfishes), rather than the African Citharinodei. Time-calibrated phylogenies indicate an ancient origin of major characoid lineages and reveal a much more recent emergence of most characoid species. Diversification rate analyses infer increased speciation and decreased extinction rates during the Oligocene at around 30 Ma during a period of mega-wetland formation in the proto-Orinoco-Amazonas. Three species-rich and ecomorphologically diverse lineages (Anostomidae, Serrasalmidae, and Characidae) that originated more than 60 Ma in the Paleocene experienced particularly notable bursts of Oligocene diversification and now account collectively for 68% of the approximately 2150 species of Characoidei. In addition to paleogeographic changes, we discuss potential accelerants of diversification in these three lineages. While the Neotropics accumulated a museum of ecomorphologically diverse characoid lineages long ago, this geologically dynamic region also cradled a much more recent birth of remarkable species-level diversity. [Biodiversity; Characiformes; macroevolution; Neotropics; phylogenomics; ultraconserved elements.]

中文翻译：

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加速多样化解释了热带Characoid鱼的特殊物种丰富性

新热带地区拥有地球上物种最丰富的淡水鱼类动物群，但这种异常多样化的时机仍不清楚。新热带地区是在其漫长的历史中稳定地积累物种，还是最近获得了非凡的多样性？生物学家长期以来一直在争论对这些博物馆和摇篮假设的相对支持，但很少有大型多样性热带进化枝的系统发育包含足够的分类群来区分它们。我们使用跨越 293 个物种、211 个属和 21 个角形鱼类科的 1288 个超保守元素基因座来重建一个新的、化石校准的系统发育，并推断出一个进化枝最可能的多样化情景，其中包括三分之一的新热带鱼类多样性。这种系统发育暗示了 Characiformes 传统划界的并系，因为它将大部分新热带 Characoidei 解析为 Siluriformes （鲶鱼）的姐妹谱系，而不是非洲 Citharinodei。时间校准的系统发育表明主要 characoid 谱系的古老起源，并揭示了大多数 characoid 物种的最近出现。多样化率分析推断，在原始奥里诺科-亚马逊河流域形成巨型湿地期间，渐新世 30 Ma 左右，物种形成增加，灭绝率降低。三个物种丰富且生态形态多样的谱系（Anostomidae，Serrasalmidae，起源于古新世超过 60 Ma 的 Characidae）经历了特别显着的渐新世多样化爆发，现在总共占大约 2150 种 Characoidei 的 68%。除了古地理变化，我们还讨论了这三个谱系多样化的潜在促进因素。虽然新热带地区很久以前就积累了生态形态多样的 characoid 谱系的博物馆，但这个地质动态的地区也孕育了一个更近的物种水平多样性的诞生。[生物多样性；叉形目; 宏观进化；新热带；系统基因组学；超保守元素。] 虽然新热带地区很久以前就积累了生态形态多样的 characoid 谱系的博物馆，但这个地质动态的地区也孕育了一个更近的物种水平多样性的诞生。[生物多样性；叉形目; 宏观进化；新热带；系统基因组学；超保守元素。] 虽然新热带地区很久以前就积累了生态形态多样的 characoid 谱系的博物馆，但这个地质动态的地区也孕育了一个更近的物种水平多样性的诞生。[生物多样性；叉形目; 宏观进化；新热带；系统基因组学；超保守元素。]