Trachypithecus laotum 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Cercopithecidae

Scientific Name: Trachypithecus laotum (Thomas, 1911)
Common Name(s):
English Laotian Langur, Lao Langur, Lao leaf monkey
French Langur du Laos
Taxonomic Notes: This taxon, here considered monotypic, is sometimes also placed as the nominate form of the species T. laotum together with the subspecies T. l. hatinhensis (Richardson et al. in press). Its taxonomic status relative to T. ebenus and T. hatinhensis requires clarification, although there is a clear genetic difference between hatinhensis and laotum (Roos 2004).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A3cd+4cd ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Timmins, R.J. & Boonratana, R.
Reviewer(s): Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
This species is listed as Vulnerable, since it is projected to undergo a decline of more than 30% over the next 3 generations (36 years, given a generation length of 12 years) due to the ongoing loss and decline of habitat and, primarily, the effects of hunting. If the form north of the Nam Theun River turns out to be a distinct taxon, then it may warrant listing in a higher category of threat.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is only known from Khammouane and Borikhamxai Provinces in Lao PDR (Le and Campbell 1993/1994, Ruggeri and Timmins 1995/1996, Groves 2001). The range north of the Nam Theun River is speculative; a langur most likely T. laotum is widely reported from limestone in this area, although there is no confirmation that is indeed T. laotum.
Countries occurrence:
Lao People's Democratic Republic
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:There is no reliable information on the population status of this species; however, it is common in suitable habitat throughout its range, which is estimated at between 500-2,000 km2 (R. Timmins pers. comm.). Reliable population estimates depend greatly on differentiating between laotum and ebenus in the Phou Hin Poun area, and also the identity of the langur occurring north of the Nam Theun River. Populations north of the Nam Theun are scarce and localized, are naturally more fragmentary, and have already declined seriously due to hunting (Ruggeri and Timmins 1995/1996, R. Timmins pers. comm.).
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species is closely associated with forests in limestone/karst environments, but is also associated with non-limestone rock outcrops on steep or precipitous mountain slopes. It is folivorous, terrestrial and arboreal, and diurnal. (Ruggeri and Timmins 1995/1996, R. Timmins pers. comm.).

Threats [top]

Major Threat(s): The major threat to the species is hunting for food and medicine (as with T. hatinhensis, there has been a shift from the use of firearms to snaring). Habitat loss is likely to be a threat in the long-term, although at present it is unlikely to be significantly influencing population trends (Ruggeri and Timmins 1995/1996, R. Timmins pers. comm.).

Conservation Actions [top]

Conservation Actions: This species is listed on CITES Appendix II, and is known to occur in 2 protected areas: Khammouane National Biodiversity Conservation Area and Nam Kading National Biodiversity Conservation Area (R. Timmins pers. comm.). There is a need for further survey work to resolve the taxonomic and population status of the langur north of the Nam Theun River.

Citation: Timmins, R.J. & Boonratana, R. 2008. Trachypithecus laotum. The IUCN Red List of Threatened Species 2008: e.T22044A9350930. . Downloaded on 20 September 2017.
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