Indochinese black langur

The Indochinese black langur (Trachypithecus ebenus) is a poorly known Old World monkey native to Laos and adjacent Vietnam.^[1] It was originally described as a subspecies of T. auratus,^[2] but was later found to be a member of the T. francoisi group, with some maintaining it as a subspecies of that species.^[1] In 2001, it was recommended treating it as a separate species.^[3]

Indochinese black langur
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Suborder:	Haplorhini
Infraorder:	Simiiformes
Family:	Cercopithecidae
Genus:	Trachypithecus
Species group:	Trachypithecus francoisi group
Species:	T. ebenus
Binomial name
Trachypithecus ebenus Brandon-Jones, 1995

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,^[1] T. ebenus showing what appears to be signs of intergradation with T. hatinhensis are known,^[4] and genetically the two barely are separable.^[5][6] This has led to suggestions that it may be a black morph of that taxon,^[7] which in turn possibly should be considered a subspecies of T. laotum.^[5][6] 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.^[8] It was formerly considered data deficient by IUCN, but they now include it in the endangered T. hatinhensis.^[9]

References

1. Brandon-Jones, D.; Eudey, A. A.; Geissmann, T.; Groves, C. P.; Melnick, D. J.; Morales, J. C.; Shekelle, M. & Stewart, C.-B (2004). "Asian primate classification". International Journal of Primatology. 25 (1): 97–164. doi:10.1023/B:IJOP.0000014647.18720.32. S2CID 29045930.
2. Bradon-Jones, D (1995). "A revision of the Asian pied leaf monkeys (Mammalia: Cercopithecidae: Superspecies Semnopithecus auratus), with the description of a new subspecies". The Raffles Bulletin of Zoology. 43: 3–43.
3. Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4. OCLC 62265494.
4. Duckworth, J. W., Salter, R. E., and Khounboline, K. (eds). 1999 Wildlife in Lao P.D.R: 1999 status report. Vientiane: IUCN, WCS and CPAWM.
5. 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.
6. Roos, C., T. Nadler, Y. P. Zhang, H. Zischler. 2001. Molecular evolution and distribution of the superspecies Trachypithecus [francoisi]. Folia Primatol. 72: 181-182.
7. black langur (Trachypithecus ebenus). Archived 2011-08-07 at the Wayback Machine EPRC. Accessed 2008-07-21
8. Nadler, T. (2010). Color variation in Hatinh langurs (Trachypithecus [laotum] hatinhensis). Vietnamese Journal of Primatology 4: 13-18.
9. Xuan Canh, L.; Khac Quyet, L.; Thanh Hai, D. & Timmins, R.J. (2008). "Trachypithecus hatinhensis". The IUCN Red List of Threatened Species. 2008: e.T40789A10354744. doi:10.2305/IUCN.UK.2008.RLTS.T40789A10354744.en.