The bird was long considered a subspecies of grey peacock-pheasant or Polyplectron bicalcaratum. The Hainan peacock-pheasant is smaller, and it possesses a short crest and ruff (Johnsgard 1986).[full citation needed] It has red facial skin as opposed to grey in the yellow-orange facial skin of the grey peacock-pheasant. Beebe (1922)[full citation needed] noted various plumage differences between the two and considered them separate species.
Due to lack of detailed taxonomic studies, whether it was truly a subspecies (Polyplectron bicalcaratum katsumatae) or a full species remained unclear. Scientists used molecular markers, including the complete mitochondrial cytochrome b gene and intron G of the nuclear ovomucoid gene, to reevaluate the taxonomy of the Hainan peacock-pheasant. The results showed phylogeographic monophyly and large genetic distance between the Hainan peacock-pheasant and the grey peacock-pheasant. Sequence differences corroborated the species-level distinction between these two peacock-pheasants, which were inferred to have diverged about 1.4±0.3 million years ago, near the time Hainan Island became separated from mainland China. BirdLife International has also decided to recognize the split of Polyplectron katsumatae from Polyplectron bicalcaratum.
Due to a very low population density in tropical forest and declining population, it is now becoming severely endangered and should be regarded as the rarest species in the order Galliformes in China. Taking more conservation action immediately to protect this endangered island endemic is imperative.
- BirdLife International (2013). "Polyplectron katsumatae". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- http://www.birdlifeforums.org/WebX?13@@.2cba6deb/1 Archived 2016-04-01 at the Wayback Machine.
- Collar, N. (2009) Hainan Peacock-Pheasant: another CR species for the IUCN Red List? G@llinformed 2: 14-19.
- del Hoyo, J., Elliott, A. & Sargatal, J. eds. (1994) Handbook of the Birds of the World. Vol. 2. New World Vultures to Guineafowl. Barcelona: Lynx Edicions.
- Madge, S. and McGowan, P. (2002) Pheasants, Partridges & Grouse. London: Christopher Helm.
- Burns, Chang; J. Wang; B. Zhang; Y.Y. Liu; Y. Liang; W. Wang; J.C. Shi; H.T. Su; W.B. Zhang, Z.W. (2008). "Molecular Evidence for Species Status of the Endangered Hainan Peacock-Pheasant". Zoological Science. 25 (1): 30–35. doi:10.2108/zsj.25.30. PMID 18275243.