Phylogeography of the Sinica Group of Macaques in the Himalayas: Taxonomic and Evolutionary Implications.

Owing to the taxonomic incongruence between the morphological features and genetic relationships of the sinica group of macaques (genus Macaca), the taxonomy of this macaque group has remained inconclusive. We aimed to resolve the taxonomic quandary and improve our understanding of the historical biogeography of the group by including macaque DNA samples from previously unsampled areas in the Himalayas. We sequenced and analyzed three mitochondrial DNA loci [cytochrome b (CYTB), cytochrome oxidase subunit 1 (COI) and D-loop; 2898 bp] for sequence polymorphism, phylogenetics, species delimitation, and ancestral area reconstruction. We confirmed the occurrence of Arunachal macaque (Macaca munzala) on the southern slopes of the Eastern Himalayas in the Xizang Zizhiqu (Tibet Autonomous Region) of China. The results revealed that the sinica group of macaques is a parapatric species group composed of seven distinct species. Phylogenetic and species delimitation analyses revealed that the two previously considered subspecies of Assamese macaques (the eastern subspecies M. assamensis assamensis and the western subspecies M. a. pelops) are two distinct species. The eastern Assamese macaque is a sister species to the Tibetan macaque, whereas the western Assamese macaque and Arunachal macaque are the closest genetic sister species. The sinica group of macaques underwent five vicariance and seven dispersal radiations in the past, which mainly coincided with the Quaternary climatic oscillations between the late Pliocene and the late Pleistocene. By integrating our phylogenetic and ancestral area reconstruction results with findings from previous paleontological and molecular studies, we propose a robust hypothesis about the phylogeography of the sinica group of macaques.