The Indochinese black langur (''Trachypithecus ebenus'') is a poorly known

lutung 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 Chin ...

native to

Laos Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...

and adjacent

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 ...

. It was originally described as 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 '' T. auratus'', but was later found to be a member of the '' T. francoisi'' group, with some maintaining it as a subspecies of that species. In 2001, it was recommended treating it as a separate species. Except for its almost entirely black pelage, it resembles the other members of the ''T. francoisi'' group. Uniquely in this group, it and the related '' T. hatinhensis'' appear to be

parapatric In parapatric speciation, two subpopulations of a species evolve reproductive isolation from one another while continuing to exchange genes. This mode of speciation has three distinguishing characteristics: 1) mating occurs non-randomly, 2) gene ...

, ''T. ebenus'' showing what appears to be signs of

intergradation In zoology, intergradation is the way in which two distinct subspecies are connected via areas where populations are found that have the characteristics of both. There are two types of intergradation: primary and secondary intergradation. Primary ...

with ''T. hatinhensis'' are known, and

genetically Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working in ...

the two barely are separable.Roos, C. 2004. ''Molecular evolution and systematics of Vietnamese primates.'' In: Nadler, T., U. Streicher, and Ha Thang Long (eds). Conservation of Primates in Vietnam: 23-28.Roos, C., T. Nadler, Y. P. Zhang, H. Zischler. 2001. ''Molecular evolution and distribution of the superspecies Trachypithecus rancoisi'' Folia Primatol. 72: 181-182. This has led to suggestions that it may be a black

morph Morph may refer to: Biology * Morph (zoology), a visual or behavioral difference between organisms of distinct populations in a species * Muller's morphs, a classification scheme for genetic mutations * "-morph", a suffix commonly used in tax ...

of that

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

,black langur (Trachypithecus ebenus).
EPRC. Accessed 2008-07-21 which in turn possibly should be considered a subspecies of '' T. laotum''. A survey that included 67 ''T. hatinhensis'' revealed a high level of variation in the amount of white to the head, and ''ebenus'' was maintained as a morph.Nadler, T. (2010). ''Color variation in Hatinh langurs (Trachypithecus aotumhatinhensis).'' Vietnamese Journal of Primatology 4: 13-18. It was formerly considered

data deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

, but they now include it in the

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

''T. hatinhensis''.

References

{{Taxonbar, from=Q1205624

Indochinese black langur The Indochinese black langur (''Trachypithecus ebenus'') is a poorly known lutung native to Laos and adjacent Vietnam. It was originally described as a subspecies of '' T. auratus'', but was later found to be a member of the '' T. francoisi'' gro ...

Primates of Southeast Asia Mammals of Laos Mammals of Vietnam