25 Most Endangered Primate Species

Kipunji (Rungwecebus kipunji) Tanzania, Primates in Peril: The World’s 25 Most Endangered Primates 2008–2010 has been compiled by the Primate Specialist Group of IUCN’s Species Survival Commission (SSC) and the International Primatological Society (IPS), in collaboration with Conservation International (CI). © CI/Illustration by Stephen D. Nash

A list of the world's 25 most endangered primate species has been published by the IUCN report, Primates in Peril: The World’s 25 Most Endangered Primates, 2008–2010. Follow link to the full 90-page report in pdf. Here's the list, by region:

Madagascar
Greater Bamboo Lemur (Prolemur simus)
Gray-headed Lemur (Eulemur cinereiceps)
Sclater’s Black Lemur/Blue-Eyed Black Lemur ( Eulemur flavifrons)
Northern sportive lemur (Lepilemur septentrionalis)
Silky Sifaka (Propithecus candidus)

Africa
Rondo Dwarf Galago (Galagoides rondoensis)
Roloway Guenon (Cercopithecus diana roloway)
Tana River Red Colobus (Procolobus rufomitratus)
Niger Delta Red Colobus Monkey (Procolobus epieni)
Kipunji (Rungwecebus kipunji)
Cross River Gorilla (Gorilla gorilla diehli)

Asia
Siau Island Tarsier (Tarsius tumpara)
Javan Slow Loris (Nycticebus javanicus)
Simakobu or Pig-Tailed Snub-Nose Langur (Simias concolor)
Delacour’s Langur (Trachypithecus delacouri)
Golden-headed Langur or Cat Ba Langur (Trachypithecus p. poliocephalus)
Western Purple-faced Langur Trachypithecus (Semnopithecus vetulus nestor)
Grey-shanked Douc Monkey (Pygathrix cinerea)
Tonkin Snub-nosed Monkey (Rhinopithecus avunculus)
Eastern Black Crested Gibbon (Nomascus nasutus)
Western Hoolock Gibbon (Hoolock hoolock)
Sumatran Orangutan (Pongo abelii)

Central and South America
Cotton-top Tamarin (Saguinus oedipus)
Variegated or Brown Spider Monkey (Ateles hybridus)
Peruvian Yellow-tailed Woolly Monkey (Oreonax flavicauda)