Presbytis hosei (Thomas, 1889)
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https://doi.org/ 10.5281/zenodo.6867065 |
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https://doi.org/10.5281/zenodo.6863386 |
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persistent identifier |
https://treatment.plazi.org/id/CE199B17-FF99-FF9D-FAE4-696CFB8DF26D |
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Jonas |
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Presbytis hosei |
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109. View Plate 47: Cercopithecidae
Hose’s Langur
French: Langur de Hose / German: Hose-Langur / Spanish: Langur de Hose
Other common names: Gray/Hose's Leaf Monkey, Hose's Grizzled Langur
Taxonomy. Semnopithecus hosei Thomas, 1889 ,
Malaysia, Sarawak, Niah.
The forms sabana and canicrus that are commonly considered to be subspecies of P. hosei are in fact distinct species, based primarily on morphological differences. The population at the type locality evidently lacks sexual dichromatism, and on this basis, two subspecies have been distinguished: hosei , supposed to be restricted to the region around Niah (possibly extending east to Brunei), lacking the sexual color difference, and everetti, named by O. Thomas in 1892, from the rest of the distribution of the species (inland eastern Sarawak, Brunei, west Sabah and northern Kalimantan) possessing it. Nevertheless, it is probable that ages of the crucial specimens, on which the distinction was made, were misunderstood; that is, they were young females instead of adults. The facial skin of P. hosei is pinkish, except for black around eyes and bluish lips. Considered monotypic here.
Distribution. NW Borneo, W Sabah State (along W coast N to Mt Kinabalu), NE Brunei, and N Sarawak State (from its type locality Niah and the lower Baram River, E inland to 2° 40’ N, and the border with N Kalimantan). View Figure
Descriptive notes. Head-body 48-56 cm, tail 65-84 cm; weight 6-7 kg (males) and 5.5-6 kg (females). Hose’s Languris iron-gray, with whitish tips on its upper side, giving an overall grizzled effect. Underside is grayish to buffy-white, becoming white on inner sides of limbs, and hands and feet are black—this tone sometimes extending to lower parts of legs. Crown crest is black, with the remainder of the crown sometimes being blackish. Facial skin is pinkish on lower jaw and cheeks, and darker (reddish or black) elsewhere. Upperparts are uniformly grayish-black. Legs are darker distally, becoming black on feet. Tail is paler below than above. Hose’s Langur is sexually dichromatic, the male having the black color restricted to its crown, with the rest of the head being white, whereas in the female, the black area also covers nape and forehead, extending laterally to ears. Juveniles are colored like adult males; typical pattern of the adult female develops at maturity.
Habitat. Lowland to hill dipterocarp rainforest (Mount Kinabalu). Elevational range is sea level to ¢.1000 m, with occasional records to 1600 m (e.g. Crocker Range) and possibly higher. Hose’s Langurs occasionally enter plantations. They are sympatric with the Maroon Langur ( P. rubicunda ) in the northern part of their distribution, the Crossmarked Langur ( P. chrysomelas ) in the western part, and the White-fronted Langur ( P. frontata ) elsewhere; but one or the other at any locality is absent or rare.
Food and Feeding. Hose’s Langurs eat mainly young leaves, along with unripe fruits, seeds, flowers, bird eggs, and nestlings. Individuals churn up and eat mud around mineral springs, which results in the formation of stomach concretions known as “bezoars” that are sought after by local people for their supposed medicinal properties.
Breeding. Infant Hose’s Langurs are white, with a black cruciform pattern across their backs and shoulders.
Activity patterns. Hose’s Languris diurnal and arboreal.
Movements, Home range and Social organization. Hose’s Languris territorial and lives in groups with one male, 2-6 females, and their young. In Brunei, the average group size 1s six. Males produce loud-calls, spacing vocalizations, which carry some distance; they are simpler in structure than those of other species of Presbytus.
Status and Conservation. CITES Appendix II. Classified as Data Deficient on The IUCN Red List (as P. hosei hose ). Although no subspecies are recognized here, the IUCN assessment included the form everetti as Vulnerable. Hose’s Langur is legally protected in Indonesia, although wrongly named P. aygula , a misidentification that may serve to subvert prosecution of offenders. P. aygula is the former name for the Javan Langur ( P. comata ), a species with which Hose’s Langur has sometimes been incorrectly lumped in the past; the original description of Simia aygula , however, was based on the long-tailed or crab-eating macaque, not on a langur at all. The conservation status of Hose’s Langur needs to be reassessed. If the sexually dichromatic form everetti is valid, then it is believed that the form hose : (sexually monochromatic) would be restricted to the northern part of the Similajau National Park (a 90km strip of forest along the Sarawak coast and now completely isolated by oil palm plantations) and possibly Brunei a little to the north-east. There is, to date, no evidence of its occurrence in Similajau (although the possibility still remains; white-whiskered individuals have been seen, but their identification is inconclusive) and surveys in Brunei are needed to confirm its continued existence there. Hose’s Languris relatively tolerant of forest disturbance and light logging, but the destruction of its forests and hunting are ongoing threats. In 2010, it was estimated that their forests had been reduced by more than 50% by settlements and primarily monoculture plantations for wood pulp and palm oil. Widespread and intense forest fires have also been problematic; they result from the drying of the forest floor because of selective (intensive) logging are serious during El Nino years. About 50,000 km? of its forests remain. The hunting of Hose’s Langurs correlates with the presence of inland settlements, the timber industry, and the demand for lucrative bezoars (a visceral mass believed to be a poison antidote that is traded to supply the traditional Chinese medicine market). Hose’s Langurs are also hunted for food and to deter crop raiding. Most of the presumed (possible) distribution of Hose’s Langur coincides with oilfields that straddle the frontier between Sarawak and Brunei. Hose’s Langur (including everett) occurs in Mount Kinabalu National Park and Lanjak-Entimau Wildlife Sanctuary in Sarawak and Sungai Kayan National Park and Betung-Kerihun National Park in Indonesia. There are no Hose’s Langurs in captivity.
Bibliography. Brandon-Jones (1996, 1997), Duckworth (1997), Duckworth et al. (2011), Goodman (1989), Groves (2001), Meijaard & Groves (2004), Mitchell, A.H. (1994, 2011), Nijman (1997c, 2001, 2004c, 2005a, 2010), Nijman, Meijaard & Hon (2008), Payne et al. (1985), Ramlee (2012), Thomas (1892).
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