The lutungs, langurs, or leaf monkeys are a group of Old World monkeys in the genus Trachypithecus (derived from Greek , meaning "rough" and , meaning "monkey"). Their range is much of Southeast Asia (northeast India, Vietnam, southern China, Borneo, Thailand, Java, and Bali). The name "lutung" comes from the Sundanese language meaning "blackness", ultimately from Proto-Austronesian *luCuŋ (which originally referred to the Formosan rock macaque); it is preferred in one paper because the authors wanted the name langurs to only refer to monkeys in the genus Semnopithecus, although some "lutungs" are now "langurs" again. Evolution Genetic analysis indicates that the ancestors of the modern species of lutung first differentiated from one another a little over 3 million years ago, during the late Pliocene. The various species alive today then diverged during the Pleistocene, presumably driven by habitat changes during the Ice Ages. The oldest fossils clearly identified as belonging to the genus date from the middle Pleistocene of Vietnam and Laos; later fossils are also known from Thailand, Java, and Sumatra. The closest living relatives of the lutungs are probably either the gray langurs or the surilis, although the exact relationships remain unclear, possibly due to hybridisation between these genera during the course of their recent evolutionary history. Taxonomy As of 2005, the authors of Mammal Species of the World recognize the following Trachypithecus species: Genus Semnopithecus formerly T. vetulus group - moved into genus Semnopithecus in most recent classifications Purple-faced langur, Semnopithecus vetulus Nilgiri langur, Semnopithecus johnii Genus Trachypithecus T. cristatus group Javan lutung, Trachypithecus auratus "Silvery lutung", silvery langur, etc.: Trachypithecus cristatus, but also used for T. germaini Indochinese lutung or Germain's langur, Trachypithecus germaini Tenasserim lutung, Trachypithecus barbei T. obscurus group Dusky leaf monkey, Trachypithecus obscurus Phayre's leaf monkey, Trachypithecus phayrei T. pileatus group Capped langur, Trachypithecus pileatus Shortridge's langur, Trachypithecus shortridgei Gee's golden langur, Trachypithecus geei T. francoisi group Francois' langur, Trachypithecus francoisi Hatinh langur, Trachypithecus hatinhensis "White-headed langur", Trachypithecus poliocephalus Laotian langur, Trachypithecus laotum Delacour's langur, Trachypithecus delacouri Indochinese black langur, Trachypithecus ebenus Since then, the T. vetulus group (the purple-faced langur and the Nilgiri langur) have been moved the genus Semnopithecus based on DNA and other evidence. In 2008, Roos et al. described the Malay Peninsula form of the silvery lutung as a separate subspecies and subsequently it has been elevated to a separate species within the T. cristatus group as the Selangor