Presbytis chrysomelas (Muller, 1838)
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publication ID |
https://doi.org/ 10.5281/zenodo.6867065 |
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https://doi.org/10.5281/zenodo.6863382 |
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persistent identifier |
https://treatment.plazi.org/id/CE199B17-FF99-FF9C-FF9A-6007F8CDFC68 |
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Jonas |
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Presbytis chrysomelas |
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107. View Plate 47: Cercopithecidae
Cross-marked Langur
Presbytis chrysomelas View in CoL
French: Langur de Bornéo / German: Sarawak-Langur / Spanish: Langur de Sarawak
Other common names: Sarawak Langur, Sarawak Surili; Bornean Banded Langur (chrysomelas), Tricolored Langur (crucigen
Taxonomy. Semnopithecus chrysomelas S. Muller, 1838 ,
Indonesia, Pontianak, West Borneo.
An isolated population is found in southeastern Sarawak State (Betong, Saribas, Nimong, Batang Lupar) that probably represents an undescribed subspecies superficially; oo similar to the “ “cross-bearing3 of morph of the subspecies cruciger. Two subspecies recognized.
Subspecies and Distribution.
P. c. cruciger Thomas, 1892 — N Borneo, from Melalap in Sabah State to the Baram District in N Sarawak. View Figure
Descriptive notes. Head—body 43-61 cm, tail 61-84 cm; weight 5.9-8.2 kg. Forehead whorls of the Cross-marked Langur, of which there is nearly always a pair, are very small and nearer the brow than in other langur species. Crest is high, upstanding, and narrow, and there is no defined fringe over eyes. There is a U-shaped parting on nape rather than a restricted whorl. Chest hairs are directed backward, meeting forward-directed belly hairs in a ridge. The “Bornean Banded Langur” (P. c. chrysomelas ) is quite variable but generally jet-black above (sometimes with a few brown hairs on back). Underside is pale whitish or fawn, the tone extending to cheeks, chin, wrists, lower thighs, and ventral surface of tail. Cheeks are brown-gray to white. The “Tricolored Langur” (P. c. cruciger) is mainly brown, with a white or creamy-fawn underside (latter tone extending to wrists, ankles, and tail tip). Forehead whorls are relatively elongated, and crest is low. There is also a strikingly different and fairly common “crossbearing” morph, in which the characteristic black cross pattern of infants is retained into adulthood. Legs, flanks, and crown are bright red. The isolated population found in south-eastern Sarawak has a less sharp dividing line between the black dorsum and red flanks, a dull creamy underside rather than white, and the chest is a more pronounced red. Black patches on knees are also more conspicuous and there is always black patching on shanks. There are two small whorls on the forehead, with a tall crest between them.
Habitat. Swamp, lowland, and mangrove forest.
Food and Feeding. The Cross-marked Langur eats leaves and fruit.
Breeding. Infant Cross-marked Langurs are whitish-gray with a distinctive, dark cross pattern along their back and shoulders.
Activity patterns. The Cross-marked Langur is diurnal and arboreal.
Movements, Home range and Social organization. The Cross-marked Langur has never been studied in the wild. It generally lives in groups of 3-7 individuals, with one male, 1-3 females, and their offspring.
Status and Conservation. CITES Appendix II. Classified as Critically Endangered on The IUCN Red Last, including both subspecies. The Cross-marked Languris legally protected in Sarawak. According to the published distributions, the Tricolored Langur occurs in Maludam, Similajau, and Tanjung Datu national parks and Samunsam Wildlife Sanctuary. It is also present in the Lingga area of Sarawak, which has been proposed as a protected area, and it may be found in Betung Kerihun National Park in Indonesia. A recent survey by K. Aken and J. W. Duckworth and colleagues has, however, reported that the Bornean Banded Langur, not the Tricolored Langur, occurs in Similajau National Park, so the respective distributions of the two subspecies (and perhaps their validity as distinct taxa) require further studies. According to its known and supposed distribution, the Bornean Banded Langur may occur in Lanjak-Entimau Wildlife Sanctuary in southwestern Sarawak near the border with West Kalimantan. The majority of the remaining populations are found in these areas, and the combined estimates for their numbers are very low, c. 200-500 individuals. Known populations of Cross-marked Langurs are believed to have been reduced by ¢.80% over the past 30 years, and certainly the area of occupancy has been reduced dramatically. It was once considered common, but now, after 100 years of intense persecution and habitat loss, it is among the rarest primates in the region, and among the rarest in the world. It occurs in less than 5% ofits historical distribution. In recent years,it has been particularly affected by expanding plantations, particularly oil palm. Additional conservation measures are urgently needed. The Crossmarked Langur could soon go extinct if current trends continue.
Bibliography. Aken (1982), Bennett & Davies (1994), Bennett et al. (1987), Brandon-Jones (1999, 2011b), Brandon-Jones et al. (2004), Duckworth (1997), Groves (2001), Meyer et al. (2011), Nijman (2001), Nijman, Hon & Richardson (2008), Payne et al. (1985).
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