The white-headed langur (''Trachypithecus leucocephalus'') is a critically endangered species of

langur The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications sp ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Guangxi Guangxi (; ; Chinese postal romanization, alternately romanized as Kwanghsi; ; za, Gvangjsih, italics=yes), officially the Guangxi Zhuang Autonomous Region (GZAR), is an Autonomous regions of China, autonomous region of the People's Republic ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

Taxonomy

It was formerly considered a subspecies of the

Cat Ba langur The Cat Ba langur (''Trachypithecus poliocephalus''), also known as the golden-headed langur, is a critically endangered species of langur endemic to Cát Bà Island, Vietnam. It is among the rarest primates in the world, and possibly the rarest ...

(''T. poliocephalus''), which is now thought to be

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...

. Its taxonomy was previously uncertain; it has been considered a partially

albinistic Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...

population of the

François' langur François' langur (''Trachypithecus francoisi''), also known as Francois' leaf monkey, the Tonkin leaf monkey, or the white side-burned black langur is a species of lutung and the type species of its species group. It is one of the least studied ...

(''T. francoisi''), a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of Francois' langur,Bradon-Jones, D. 1995. A revision of the Asian pied leaf monkeys (Mammalia: Cercopithecidae: Superspecies ''Semnopithecus auratus''), with the description of a new subspecies. ''Raffles Bull. Zool.'' 43: 3-43 a valid species (''T. leucocephalus''), or a subspecies, ''T. poliocephalus leucocephalus''. However, the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

and

American Society of Mammalogists The American Society of Mammalogists (ASM) was founded in 1919. Its primary purpose is to encourage the study of mammals, and professions studying them. There are over 4,500 members of this society, and they are primarily professional scientists ...

now recognize it as a distinct species based on a 2007 study which split both species. Populations of this species in

Chongzuo Chongzuo (; za, Cungzcoj) is a prefecture-level city in the south of Guangxi Zhuang Autonomous Region near the Sino-Vietnamese border. It is home to one of China's largest Zhuang populations. Geography and climate Chongzuo is located in sout ...

and

Fusui Fusui County is a county in the southwest of Guangxi, China. It is the easternmost county-level division of the prefecture-level city of Chongzuo. Geography Fusui is located in southwestern Guangxi and in eastern Chongzuo City. It borders Qingxi ...

display notable genetic divergence from the rest of the species, and it has thus been proposed they be treated as evolutionarily significant units.

Description

This species is blackish in color with white crown, cheeks, and neck (in contrast to the similar ''T. poliocephalus'', which has a golden crown, cheeks, and neck).White-headed langur (''Trachypithecus poliocephalus'').
ARKive. Accessed 2008-07-15

Distribution

This species has a very small range in the province of

in southernmost

, where it is known from a few scattered populations. The

Zuo River The Zuo River (, vi, Tả Giang) is a river of Guangxi, China. It begins from the confluence of the Bằng River and Kỳ Cùng River near Longzhou and joins the You River ("Right River") near Nanning to form the Yong River. These rivers form pa ...

separates this species from Francois' langur, which is found to the north.

Status

This species is considered critically endangered on the

. It is thought to have a population of no more than 600 individuals with roughly 250 mature individuals. None of the subpopulations of this species have more than 25 individuals. The main threat to this species is

poaching Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...

and to a lesser extent

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

. In addition, Francois' langurs have been released within the species' range and they have been known to

hybridize Hybridization (or hybridisation) may refer to: *Hybridization (biology), the process of combining different varieties of organisms to create a hybrid *Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals *Nu ...

with the white-headed langur, which may be genetically detrimental to it.

References

{{Taxonbar, from=Q28466511 white-headed langur Primates of East Asia Mammals of China Endemic fauna of China Critically endangered fauna of Asia white-headed langur