Abstract
Chinese Trachypithecus, which currently contains 20 species divided into four groups, is the most speciose and geographically dispersed genus among Asian colobines. Despite several morphological and molecular studies, however, its evolutionary history and phylogeography remain poorly understood. Phayre's langur ( Trachypithecus phayrei) is one of the most widespread members of the genus, but details on its actual distribution and intraspecific taxonomy are limited and controversial. Thus, to elucidate the evolutionary history of Trachypithecus and to clarify the intraspecific taxonomy and distribution of T. phayrei, we sequenced 41 mitochondrial genomes from georeferenced fecal samples and museum specimens, including two holotypes. Phylogenetic analyses revealed a robustly supported phylogeny of Trachypithecus, suggesting that the T. pileatus group branched first, followed by the T. francoisi group, and the T. cristatus and T. obscurus groups most recently. The four species groups diverged from each other 4.5-3.1 million years ago (Ma), while speciation events within these groups occurred much more recently (1.6-0.3 Ma). Within T. phayrei, we found three clades that diverged 1.0-0.9 Ma, indicating the existence of three rather than two taxa. Following the phylogenetic species concept and based on genetic, morphological, and ecological differences, we elevate the T. phayrei subspecies to species level, describe a new species from central Myanmar, and refine the distribution of the three taxa. Overall, our study highlights the importance of museum specimens and provides new insights not only into the evolutionary history of T. phayrei but the entire Trachypithecus genus as well. 叶猴属 Trachypithecus在亚洲疣猴中多样性最高、地理分布最广，目前已知20种，其多样性被划分为四大种组。尽管已有部分研究利用形态学和分子系统学证据对该属开展了部分工作，目前对于其演化历史和系统地理学仍知之甚少。其中，菲氏叶猴 Trachypithecus phayrei是叶猴属分布最广的物种之一，但目前对于该种的种下分类及不同亚种的具体分布还存在争议。因此，为了更好的探究叶猴属的系统演化关系，同时理清菲氏叶猴的种下分类问题，本研究通过对野外粪便样品及博物馆实体标本的研究分析，获得了包括2分模式标本在内的41份线粒体基因组数据，并以此构建了叶猴属系统演化关系。结果成功解析了叶猴属物种间的演化关系，并指出戴帽叶猴 T. pileatus种组的物种首先从其余物种中分化，其次是黑叶猴 T. francoisi种组，而银叶猴种组 T. cristatus和郁乌叶猴 T. obscurus种组分化最晚。四大种组相互分化的时间大约在4.5–3.1个百万年前，而每个种组内物种形成的时间则更晚，约在1.6–0.3个百万年前。就菲氏叶猴而言，结果显示其包含了3个分化时间在1.0–0.9个百万年的支系，暗示了其实际包括了3个独立物种。基于系统演化物种概念，在综合考虑形态、分子和生态学差异后，本研究将原菲氏叶猴的滇西亚种 T. p. shanicus提升至种级，并在此将缅甸中部的种群描述为一新种，并更新了厘定后三种的具体分布信息。本研究结果再次表明了博物馆馆藏标本对于科学研究的重要性，同时为整个叶猴属及菲氏叶猴这一物种的系统演化关系提供了更新数据。.