Horned guan

The horned guan (Oreophasis derbianus) is a large, approximately 85 cm long, turkey-like bird with glossed black upperparts plumage, red legs, white iris, yellow bill and a red horn on top of head. The breast and upper belly are white, and its long tail feathers are black with white band near base. Both sexes are similar. The young is duller with smaller horn, and has brown tail and wings.

Horned guan
at the Saint Louis Zoological Park
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Galliformes
Family: Cracidae
Subfamily: Oreophasinae
Sclater & Salvin, 1870
Genus: Oreophasis
G.R. Gray, 1844
Species:
O. derbianus
Binomial name
Oreophasis derbianus
Gray, 1844

The only member in monotypic genus Oreophasis, the horned guan is distributed in humid mountain forests of southeast Mexico-(Chiapas) and Guatemala of Central America. It is found in altitude up to 3,350 metres. Its diet consists mainly of fruits, green leaves and invertebrates. The female usually lays up to two eggs.

The horned guan is not a true guan, but merely resembles these birds most in overall shape and color, whereas the horn is more reminiscent of the helmeted curassows. In fact, this species is the only survivor of a very ancient lineage of cracids that has been evolving independently from all other living members of this family for at least 20, possibly as much as 40 million years.

Although it does not have any really close relatives among living cracids, the true guans are apparently most distant. Given that the basal relationships of the living cracids are not well resolved, the horned guan is often placed into a distinct subfamily, the Oreophasinae. Alternatively, it might be included in a large Cracinae with curassows and chachalacas (Pereira et al. 2002)

Due to ongoing habitat loss, small population size, limited range and hunting in some areas, the horned guan is evaluated as Endangered on the IUCN Red List of Threatened Species. It is listed on Appendix I of CITES.

Taxonomy

The holotype specimen of “Oreophasis Derbianus" G.R. Gray (Gen. Bds., 3, 1844, p.(485).) is held in the collections of National Museums Liverpool at World Museum, with accession number D210. The specimen was collected from Volcán de Fuego, Guatemala by Don Joaquin Quinones circa 1843 and came to the Liverpool national collection via the 13th Earl of Derby’s collection which was bequeathed to the people of Liverpool.

References

  • Pereira, Sérgio Luiz; Baker, Allan J.& Wajntal, Anita (2002): Combined nuclear and mitochondrial DNA sequences resolve generic relationships within the Cracidae (Galliformes, Aves). Systematic Biology 51(6): 946-958. doi:10.1080/10635150290102519 PMID 12554460 PDF fulltext


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