Miller's Grizzled Surili Presbytis hosei canicrus Miller, 1934 Indonesia (E. Central Kalimantan) (2004) The grizzled surili relies on a single national park in Borneo for its protection — but even this small refuge is almost destroyed from squatters, logging and illegal development.

All four subspecies of the Asian colobine monkey Presbytis hosei are endemic to north Borneo. The high forehead and crest linking it with the white-fronted surili (P. frontata) from the southern part of the island, mark the crested grizzled surili, P. h. sabana (Thomas, 1893) from eastern Sabah (East Malaysia) as the most divergent subspecies. Its western neighbor, Everett's grizzled surili, P. h. everetti (Thomas, 1893) is unique to the genus in being sexually dichromatic. The bandanna-like white tract of hair across the forehead of juveniles and male adults is reduced to a white spot in female adults. In the south-eastern subspecies, Miller's grizzled surili (P. h. canicrus), all adults and juveniles much resemble adult female P. h. everetti, but have no frontal white spot. P. h. canicrus is known only from the north-east Indonesian part of Borneo as far south as the Kutai National Park, the only protected part of its recorded range (Brandon-Jones, 1997). Only an estimated 5% of the forest in this National Park has escaped timber concessions, illegal settling, industrial development and fire (Meijard and Nijman, 2000). This leaves P. h. canicrus probably critically endangered or even extinct, although no surveys have been undertaken. The western subspecies, Hose's grizzled surili, P. h. hosei (Thomas, 1889), is even more likely to be extinct as most of its distribution coincides with that of the oilfields which straddle the frontier between Sarawak (East Malaysia) and Brunei. P. h. hosei resembles P. h. everetti, but the female retains her juvenile color at maturity (Brandon-Jones, 1997). There is a slim chance that P. h. hosei survives in the northern part of the Similajau National Park in central coastal Sarawak (Duckworth, 1995, 1998). Populations may also exist in Brunei which have been much less subject to hunting and deforestation, but they are likely to be intermediate with P. h. everetti. The reputed medicinal value of the bezoar stones sometimes formed in the gut makes this species a target even for hunters uninterested in its meat. Douglas Brandon-Jones

References Brandon-Jones, D. 1997. The zoogeography of sexual dichromatism in the Bornean grizzled sureli, Presbytis comata (Desmarest, 1822). Sarawak Museum Journal 50(71): 177-200. Duckworth, J. W. 1995. Mammal records from Similajau National Park. Sarawak Museum Journal 48: 157-161. Duckworth, J. W. 1998. Mammals in Similajau National Park, Sarawak, in 1995. Sarawak Museum Journal 51: 171-192. Meijard, E. and Nijman, V. 2000. Distribution and conservation of the proboscis monkey (Nasalis larvatus) in Kalimantan, Indonesia. Biological Conservation 92: 15-24. Suggested citation: Brandon-Jones, D. 2005. Miller's Grizzled Surili, Presbytis hosei canicrus Miller, 1934. In: Primates in Peril: The World's 25 Most Endangered Primates 2004-2006, R. A. Mittermeier, C. Valladares-Pádua, A. B. Rylands, A. A. Eudey, T. M. Butynski, J. U. Ganzhorn, R. Kormos, J. M. Aguiar and S. Walker (eds.), p.26. Report to IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS) and Conservation International (CI), Washington, DC.