Almost half of currently recognised primate species are threatened. However, the exact number of species at risk is still unclear due to our lack of understanding of primate diversity. This is largely due to reliance on morphological traits for taxonomy and species delimitation. Thus it is imperative that we use multidisciplinary approaches to resolve the taxonomy of problematic groups.

Hanuman langur, Semnopithecus entellus, is a widely distributed nonhuman primate in the Indian Subcontinent. It is found in India, Sri Lanka, Nepal and in parts of Pakistan, Bhutan and Bangladesh. Morphological variation has long been recognised in these langurs, which is reflected in the multitude of classification schemes. A recent study on the Hanuman langur populations in south India used a multiordinate approach which led to re-description of three species. However, considerable ambiguities still exist among the populations in the north. According to the available literature, there are three morphologically distinct populations of Hanuman langurs in the Himalayas, whose taxonomic status is unclear. By systematic sampling across the Himalayas and constructing robust phylogenies using molecular and morphological traits and demarcating species boundaries using ecological niche modelling will help in resolving the taxonomic status of these langurs.

Successful conservation of a species is only possible when the distribution and classification is well resolved. With this study, we aim to resolve the classification and its distribution limits. This will help in setting up meaningful conservation goals.