Malayan Peacock-Pheasant - Systematics

Systematics

mtDNA cytochrome b and D-loop as well as the nuclear ovomucoid intron G sequence data places the Malayan Peacock-Pheasant within the basal radiation of its genus, together with the even more elusive Bornean Peacock-Pheasant (P. schleiermacheri) – its sister species –, and the even more basal Palawan Peacock-Pheasant (P. napoleonis). The common ancestor of the Malay and Bornean Peacock-Pheasants probably diverged from its relatives during the Pliocene or maybe Late Miocene, about 5 million years ago (Ma) perhaps.

When the lineages of Borneo and Malaya diverged has not been studied; considering the phylogeny of Polyplectron, an Early Pleistocene date, roughly around 1 Ma, seems reasonable. In that regard, it is probably significant that Borneo was connected to the Southeast Asian mainland during Pleistocene glacial periods with low sea levels. In any case, the phylogeny and biogeography of the basal peacock-pheasants agrees with the idea of reproductive isolation due to rising sea levels during the last ice age's interglacials, whereas the more advanced Polyplectron species are limited to today's mainland Southeast Asia.