Is Malaysia's banded langur, Presbytis femoralis femoralis, actually Presbytis neglectus neglectus? Taxonomic revision with new insights on the radiation history of the Presbytis species group in Southeast Asia

Ethnoprimatology reveals new extended distribution of critically endangered banded langur Presbytis femoralis (Martin, 1838) in Pahang, Malaysia: Insights from indigenous traditional knowledge and molecular analysis

The banded langur (Presbytis femoralis) is a critically endangered primate, restricted to Johor, Malaysia, with an estimated population size of less than 500 individuals. Traditionally, distribution studies on this highly threatened primate have relied on conventional methods such as DNA identification, live counting, and camera trapping. However, ethnoprimatology offers an alternative approach to data collection, involving the active participation of indigenous and local communities possessing valuable knowledge and experience with local primate species. This study employed an integrated approach incorporating ethnoprimatology by utilizing pooled local expert opinion, local surveys, interviews, and fecal DNA analysis, resulting in a novel distribution range for the banded langur. The combination of expert opinions revealed this species' most optimistic distribution scenario across Johor and Pahang, inhabiting various ecosystems, including lowland forests, peat swamps, and human-modified landscapes. Further interviews and surveys conducted within the Orang Asli community in Tasik Chini and Tasek Bera have provided additional support for the revised distribution, documenting occurrences of banded langur utilization in indigenous practices, such as food consumption, cultural beliefs, medicinal applications, and craftsmanship. Phylogenetic analysis demonstrated genetic differentiation between populations in Johor and Pahang, with the populations in the southern part of Peninsular Malaysia likely serving as ancestral sources for other populations. Consequently, this study not only elucidated the updated distribution of banded langur through DNA records and direct observations but also established the efficacy of ethnoprimatology as a precursory tool for uncovering the present distribution patterns of other primate species in Malaysia.

Molecular phylogeny confirms the subspecies delineation of the Malayan Siamang (Symphalangussyndactyluscontinentis) and the Sumatran Siamang (Symphalangussyndactylussyndactylus) based on the hypervariable region of mitochondrial DNA

Siamangs (Symphalangussyndactylus) are native to Peninsular Malaysia, Sumatra and southern Thailand and their taxonomical classification at subspecies level remains unclear. Morphologically, two subspecies were proposed as early as 1908 by Thomas namely Symphalangus s.syndactylus and Symphalanguss.continentis. Thus, this study aims to clarify the Siamang subspecies status, based on mtDNA D-loop sequences. Faecal samples were collected from wild Siamang populations at different localities in Peninsular Malaysia. A 600-bp sequence of the mitochondrial D-loop region was amplified from faecal DNA extracts and analysed along with GenBank sequences representing Symphalangus sp., Nomascus sp., Hylobates sp., Hoolock sp. and outgroups (Pongopygmaeus, Macacafascicularis and Papiopapio). The molecular phylogenetic analysis in this study revealed two distinct clades formed by S.s.syndactylus and S.s.continentis which supports the previous morphological delineation of the existence of two subspecies. Biogeographical analysis indicated that the Sumatran population lineage was split from the Peninsular Malaysian population lineage and a diversification occurrred in the Pliocene era (~ 3.12 MYA) through southward expansion. This postulation was supported by the molecular clock, which illustrated that the Peninsular Malaysian population (~ 1.92 MYA) diverged earlier than the Sumatran population (~ 1.85 MYA). This is the first study to use a molecular approach to validate the subspecies statuses of S.s.syndactylus and S.s.continentis. This finding will be useful for conservation management, for example, during Siamang translocation and investigations into illegal pet trade and forensics involving Malayan and Sumatran Siamangs.

Taxonomic Revision and Evolutionary Phylogeography of Dusky Langur (Trachypithecus obscurus) in Peninsular Malaysia

Dusky langur, Trachypithecus obscurus, inhabits tropical rainforests in Peninsular Malaysia, Thailand, and Myanmar. Morphologically, five subspecies are distributed in Peninsular Malaysia, but few studies have used genetic data to verify the classification. It is difficult to differentiate subspecies based on morphological characteristics, so this study used molecular data to differentiate subspecies of T. obscurus. The issue was addressed by analyzing 723 and 649 base pairs of the mitochondrial D-loop region and COI, respectively. DNA amplifications were performed using species-specific primer toward 35 individuals representing different populations. Phylogenetic analyses showed that two main clades representing populations in southern and northern Peninsular Malaysia. The results demonstrate that subspecies of T. obscurus in Peninsular Malaysia does not support classification based on the morphology that recognizes five subspecies. Previous study based on morphology that classified the subspecies on Perhentian Island, Terengganu, as T. obscurus styx is not recognized in this study. This subspecies happened to merge with the population in northern Peninsular Malaysia. Trachypithecus o. styx probably inhabited the southern peninsula and, due to the terminal Pleistocene sea level rise, spread to the east coast but could not spread farther because the subspecies was situated on offshore islands during the period. This assumption was supported by the molecular clock, which showed that subspecies on Perhentian Island spread after the Perlis population (T. obscurus flavicauda).

Faecal DNA to the rescue: Shotgun sequencing of non-invasive samples reveals two subspecies of Southeast Asian primates to be Critically Endangered species

A significant number of Southeast Asian mammal species described in the 19^th and 20^th century were subsequently synonymized and are now considered subspecies. Many are affected by rapid habitat loss which creates an urgent need to re-assess the conservation status based on species boundaries established with molecular data. However, such data are lacking and difficult to obtain for many populations and subspecies. We document via a literature survey and empirical study how shotgun sequencing of faecal DNA is a still underutilized but powerful tool for accelerating such evaluations. We obtain 11 mitochondrial genomes for three subspecies in the langur genus Presbytis through shotgun sequencing of faecal DNA (P. femoralis femoralis, P. f. percura, P. siamensis cf. cana). The genomes support the resurrection of all three subspecies to species based on multiple species delimitation algorithms (PTP, ABGD, Objective Clustering) applied to a dataset covering 40 species and 43 subspecies of Asian colobines. For two of the newly recognized species (P. femoralis, P. percura), the results lead to an immediate change in IUCN status to Critically Endangered due to small population sizes and fragmented habitats. We conclude that faecal DNA should be more widely used for clarifying species boundaries in endangered mammals.