WNomascus is the second-most speciose genus of gibbons. Originally, this genus was a subgenus of Hylobates, and all individuals were considered one species, Hylobates concolor. Species within Nomascus are characterized by 52 chromosomes. Some species are all black, some are light with a distinct black tuft of crown fur, and some have distinct, light-colored cheek patches. Nomascus is found from southern China (Yunnan) to southern Vietnam, and also on Hainan Island. One species, Nomascus nasutus, has been deemed "the most critically endangered ape species in the world". All species in this genus are either endangered or critically endangered.
WThe black crested gibbon is an endangered species of gibbon found in China, Laos, and northern Vietnam, with four subspecies.
WThe eastern black crested gibbon, also known as the Cao-vit black crested gibbon or the Cao-vit crested gibbon, is a species of gibbon from southeast China and northern Vietnam.
WThe Hainan black-crested gibbon or Hainan gibbon, is a species of gibbon found only on Hainan Island, China. It was formerly considered a subspecies of the eastern black crested gibbon from Hòa Bình and Cao Bằng provinces of Vietnam and Jingxi County in Guangxi Zhuang Autonomous Region, China. Molecular data, together with morphology and call differences, suggest it is a separate species. Its habitat consists of broad-leaved forests and semi-deciduous monsoon forests. It feeds on ripe, sugar-rich fruit, such as figs and, at times, leaves, and insects.
WThe northern white-cheeked gibbon is a species of gibbon native to South East Asia. It is closely related to the southern white-cheeked gibbon, with which it was previously considered conspecific. The females of the two species are virtually indistinguishable in appearance.
WThe southern white-cheeked gibbon is a species of gibbon native to Vietnam and Laos. It is closely related to the northern white-cheeked gibbon and the yellow-cheeked gibbon ; it has previously been identified as a subspecies of each of these.
WThe yellow-cheeked gibbon, also called the golden-cheeked gibbon, yellow-cheeked crested gibbon, the golden-cheeked crested gibbon, red-cheeked gibbon, or the buffed-cheeked gibbon, is a species of gibbon native to Vietnam, Laos, and Cambodia.. The species was discovered and named after the British naturalist Gabrielle Maud Vassal.