Mixed-species associations and attempted mating suggest hybridization between purple-faced and tufted gray langurs of Sri Lanka.

Hybridization is increasingly recognized as an important mechanism of evolutionary change in the order Primates. Here, we present the first observational data supporting natural hybridization between the critically endangered purple-faced langur (Semnopithecus vetulus philbricki) and the threatened tufted gray langur (Semnopithecus priam thersites) in Kaludiyapokuna Forest Reserve in Sri Lanka. In one case study, we observed a long-term (> 1 year) mixed-species group consisting of one adult tufted gray langur male coexisting with seven adult purple-faced females. Although copulations were not observed, two infants were conceived during the male's tenure, and the coat color of one of these infants transitioned into that intermediate between those of the two langur species. The tufted gray langur male was also aggressive toward extra-group males of both species, as well as towards purple-faced juveniles within his group. However, we never witnessed the male exhibiting aggression towards the infants conceived during his tenure. In a second case study, a female purple-faced langur visited and sexually solicited a tufted gray langur male in a known study group of this species over the course of 2 days, in what resembled a sexual consortship. Taken together, the observed mixed-species association and attempted interspecific mating suggest that hybridization is very likely in these sympatric species. Genetic data are needed to confirm and determine the extent of hybridization in the dry zone of Sri Lanka where purple-faced langurs live in sympatry with tufted gray langurs.

Mitogenomic phylogeny of the Asian colobine genus Trachypithecus with special focus on Trachypithecus phayrei (Blyth, 1847) and description of a new species.

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.

Presbytis neglectus or P. femoralis, Colobine Molecular Phylogenies, and GenBank Submission of Newly Generated DNA Sequences.

Great progress has been made in unravelling the evolutionary history of Asian colobines, largely through the use of dated molecular phylogenies based on multiple markers. The Presbytis langurs are a case in point, with more allopatric species being identified, recognition of Presbytis thomasi from Sumatra rather than P. potenziani from the Mentawai Islands as being the most basal species of the group, and the discovery that P. rubicunda from Borneo is nested among the Sumatran species and only made it to Borneo in the last 1.3 million years. Based on variation in mitochondrial d-loop, it has recently been argued that Malaysia's P. femoralis femoralis is actually P. neglectus neglectus. Unfortunately, despite being available, sequences from the type locality, Singapore, were excluded from the analysis, and none of the newly generated sequences was deposited in GenBank. I manually reconstructed these sequences, which allowed me to present a molecular phylogeny that includes 8 additional sequences from West Malaysia and Singapore. P. neglectus from Malaysia and P. femoralis from Singapore form one monophyletic clade, with minimal divergence. I conclude that recognition of P. neglectus is erroneous and the name is a junior synonym of P. femoralis. Colobine taxonomy and systematics have advanced, and continue to advance, mostly by considering evidence from a wide range of individuals, species and data sets (molecular, behavioural and morphological) rather than focusing on single molecular markers from 1 or 2 species from one small geographic area. For an orderly taxonomic debate where evidence can be evaluated and reinterpreted it is essential that newly generated sequences are deposited in public repositories.

A high-quality genome assembly for the endangered golden snub-nosed monkey (Rhinopithecus roxellana).

BACKGROUND: The golden snub-nosed monkey (Rhinopithecus roxellana) is an endangered colobine species endemic to China, which has several distinct traits including a unique social structure. Although a genome assembly for R. roxellana is available, it is incomplete and fragmented because it was constructed using short-read sequencing technology. Thus, important information such as genome structural variation and repeat sequences may be absent. FINDINGS: To obtain a high-quality chromosomal assembly for R. roxellana qinlingensis, we used 5 methods: Pacific Bioscience single-molecule real-time sequencing, Illumina paired-end sequencing, BioNano optical maps, 10X Genomics link-reads, and high-throughput chromosome conformation capture. The assembled genome was ∼3.04 Gb, with a contig N50 of 5.72 Mb and a scaffold N50 of 144.56 Mb. This represented a 100-fold improvement over the previously published genome. In the new genome, 22,497 protein-coding genes were predicted, of which 22,053 were functionally annotated. Gene family analysis showed that 993 and 2,745 gene families were expanded and contracted, respectively. The reconstructed phylogeny recovered a close relationship between R. rollexana and Macaca mulatta, and these 2 species diverged ∼13.4 million years ago. CONCLUSION: We constructed a high-quality genome assembly of the Qinling golden snub-nosed monkey; it had superior continuity and accuracy, which might be useful for future genetic studies in this species and as a new standard reference genome for colobine primates. In addition, the updated genome assembly might improve our understanding of this species and could assist conservation efforts.