The eastern black-crested gibbon (Nomascus nasutus), 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. The term "Cao-vit" originated from the sounds of their calls or songs that villagers of Ngoc Khe, Phong Nam and Ngoc Con communes of Trung Khanh District, Cao Bang Province of Vietnam use to name for them. This name was officially used by gibbon experts since the rediscovery.[3]
| Eastern black crested gibbon | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Haplorhini |
| Infraorder: | Simiiformes |
| Family: | Hylobatidae |
| Genus: | Nomascus |
| Species: | N. nasutus
|
| Binomial name | |
| Nomascus nasutus (Künckel d'Herculais, 1884)
| |
| |
| Eastern black crested gibbon range | |
From the 1960s until the 2000s there had been no confirmed sightings of the eastern black-crested gibbon and it was thought to be possibly extinct. In 2002 a small population was rediscovered by two FFI biologists in a karst forest of Trùng Khánh District, Cao Bằng Province, in northeast Vietnam.[4][5] The species was endemic to Vietnam until 2006 when they were also found in a small forest in Guangxi Province of China, which is adjacent to Trung Khanh forests.[6] In 2005 it was estimated that this population in Vietnam side was about 35–37 individuals.[7]
The eastern black crested gibbon is one of the rarest and most critically endangered primates in the world. This status has resulted from deforestation of its habitat, encroachment, and poaching.
Taxonomy edit
The eastern black crested gibbon is classified as separate from other crested gibbons based on molecular data, fur coloration, and differences in vocal communication. Previously it had been considered conspecific with the Hainan black crested gibbon or as a subspecies of the black crested gibbon. Until the sequencing of the mitochondrial cytochrome b gene the Hainan black crested gibbon was thought to be Nomascus nasutus hainanus, a subspecies of eastern black crested gibbon. The researchers proposed that the genetic separation showed it was a distinct species.[8]
References edit
- ^ Rawson, B.M.; Roos, C.; Nguyen, M.H.; Bleisch, W.; Geissmann, T.; Fan, P.F. (2020). "Nomascus nasutus". IUCN Red List of Threatened Species. 2020: e.T41642A17969578. doi:10.2305/IUCN.UK.2020-2.RLTS.T41642A17969578.en. Retrieved 19 November 2021.
- ^ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
- ^ Geissmann, Thomas; La, Quang Trung; Trinh, Dinh Hoang; Vu, Dinh Thong; Dang, Ngoc Can (2003-01-01). "Rarest ape rediscovered in Vietnam". Asian Primates. 8.
- ^ La Quang Trung; Trinh Dinh Hoang (2002). "Report on survey of eastern black crested gibbon (Nomascus sp. cf. nasutus) in Trung Khanh District, Cao Bang Province". Fauna & Flora International Indochina Programme. Hanoi, Vietnam.
- ^ "Rarest ape species rediscovered in Vietnam". www.gibbons.de. Retrieved 2021-10-07.
- ^ Chan, Bosco; Tan, X.F.; Tan, W.J. (2008). "Rediscovery of the critically endangered eastern black-crested gibbon Nomascus nasutus (Hylobatidae) in China, with preliminary notes on population size, ecology and conservation status". Asian Primates Journal. 1: 17–25.
- ^ Vu Ngoc Thanh, Nguyen Xuan Dang, Nguyen Manh Ha, Luu Tuong Bach, Nguyen Thi Hien (2005). Survey and assessment of the Cao-vit gibbon population in Phong Nam – Ngoc Khe Proposed Species/habitat Conservation Area, Trung Khanh District, Cao Bang Province. Fauna & Flora International, Vietnam.
- ^ Roos, C.; Thanh, V. N.; Walter, L.; Nadler, T. (2007). "Molecular systematics of Indochinese primates" (PDF). Vietnamese Journal of Primatology. 1: 41–53.