Trachypithecus

Trachypithecus is a genus of Old World monkeys whose members are known as lutungs, langurs or leaf monkeys. Their range covers much of Southeast Asia, including northeast India, Vietnam, southern China, Borneo, Thailand, Java and Bali. The name lutung comes from the Sundanese word for blackness, and the scientific name comes from the Ancient Greek words for rough and monkey. Genetic analysis indicates that the ancestors of the modern species first differentiated a little over three million years ago, in the late Pliocene, and that the species alive today diverged during the Pleistocene, probably driven by habitat changes in the Ice Ages. The oldest fossils clearly belonging to the genus come from the middle Pleistocene of Vietnam and Laos. The closest living relatives of the lutungs are probably either the gray langurs or the surilis, although the exact relationships remain unclear, possibly because of hybridisation between these genera in their recent evolutionary history. Lutungs have a rather slim build with a long tail. Species such as the Nilgiri langur and the purple-faced langur were once placed here but have been moved to Semnopithecus on the evidence of DNA.