A combined approach of mitochondrial DNA and anchored nuclear phylogenomics sheds light on unrecognized diversity, phylogeny, and historical biogeography of the cascade frogs, genus Amolops (Anura: Ranidae)

Amolops is one of the most species-rich genera in Ranidae, with 59 recognized species. This genus currently includes six species groups diagnosed mainly by morphology. Several recent molecular studies indicated that the classification of species groups within Amolops remains controversial, and key nodes in the phylogeny have been inadequately resolved. In addition, the diversity of cascade frogs remains poorly understood, especially for those from incompletely sampled regions. Herein, we investigate the species-level diversity within genus Amolops throughout southern China and Southeast Asia, and infer evolutionary relationships among the species using mtDNA data (16S, COI, and ND2). Molecular analyses indicate nine new unnamed species, mostly distributed in the Himalayas. We then utilized anchored hybrid enrichment to generate a dataset representing major mitochondrial lineages to resolve phylogenetic relationships, biogeography, and pattern of species diversification. Our resulting phylogeny strongly supports the monophyly of three previously identified species groups (the A. ricketti, A. daiyunensis, and A. hainanensis groups), the paraphyly of the A. mantzorum and A. marmoratus groups, as previously defined, and monophyly of the A. monticola group. We erect one new species group, the A. viridimaculatus group, and recognize Dubois (1992) 'subgenus' Amo as the A. larutensis species group. Biogeographic analysis suggests that Amolops originated on the Indo-Burma/Tai-Malay Peninsula at the Eocene/Oligocene boundary, and dispersed outward, exemplifying a common pattern observed for the origin of Asia's biodiversity. The early divergence within Amolops coincides with the Himalayas uplift, and the lateral extrusion of Indochina at the Oligocene/Miocene boundary. Our results show that paleoclimatic and geomorphological events have profoundly influenced the pattern of lineage diversification within Amolops.

湍蛙属（Amolops）是蛙科（Ranidae）中物种多样性最高的属之一，目前已被正式描述的物种共计59种。该属当前可划分为6个物种组，其分类界定主要依据形态学特征。近年来多项分子生物学研究显示，湍蛙属内的物种组分类体系仍存在较大争议，系统发育树中的关键节点尚未得到充分解析。此外，湍蛙的物种多样性仍有待系统探究，尤其是来自采样覆盖尚不充分区域的类群。
本研究针对分布于中国南方及东南亚地区的湍蛙属开展物种水平多样性调查，并依托线粒体DNA（mtDNA）数据（包含16S rRNA、COI及ND2基因片段）解析该属物种间的演化亲缘关系。分子分析结果共检出9个未命名的新物种，其中绝大多数分布于喜马拉雅山脉区域。
本研究进一步采用锚定杂交富集技术，构建了覆盖主要线粒体谱系的分子数据集，用以解析湍蛙属的系统发育关系、生物地理格局及物种多样化模式。系统发育分析结果强力支持此前定义的3个物种组——里克特湍蛙组（A. ricketti）、大云湍蛙组（A. daiyunensis）及海南湍蛙组（A. hainanensis）为单系群；同时验证了原界定的曼氏湍蛙组（A. mantzorum）和斑玛湍蛙组（A. marmoratus）为并系群，而山湍蛙组（A. monticola）为单系群。本研究新建1个物种组——绿斑湍蛙组（A. viridimaculatus），并将Dubois（1992）提出的‘亚属’Amo 修订为卢拉特湍蛙物种组（A. larutensis）。
生物地理分析结果表明，湍蛙属起源于始新世/渐新世交界时期的印缅地区/泰马半岛，随后向外扩散，这一演化模式契合亚洲生物多样性起源的常见规律。湍蛙属的早期分化事件与喜马拉雅山脉抬升及渐新世/中新世交界时期印支地块的侧向挤出时间高度吻合。本研究结果证实，古气候与古地貌事件对湍蛙属的谱系分化格局产生了深刻影响。

搜集汇总

背景与挑战

背景概述

该数据集通过结合线粒体DNA和锚定核系统基因组学方法，对Amolops属瀑布蛙进行了全面研究，揭示了9个新物种（主要分布在喜马拉雅地区）并重新评估了物种组分类。研究还阐明了该属的起源和分化历史，表明其起源于始新世/渐新世边界的印缅/泰马半岛，早期分化与喜马拉雅隆起等地质事件密切相关。