The systematics of the genus are somewhat unclear. The species of Polyplectron evolved at some time between, roughly, the Early Pliocene and the Middle Pleistocene, or 5-1 mya. The morphologically somewhat aberrant Polyplectron malacense and its little-known sister species P. schleiermacheri form a basal radiation around the southern South China Sea together with the striking P. napoleonis, as is confirmed by comparison of biogeography and mtDNA cytochrome b and D-loop as well as the nuclear ovomucoid intron G (Kimball et al. 2001).
The relationships of the other forms are more poorly understood. P. germaini and P. bicalcaratum are similar in morphology and are nearly parapatric; the molecular data suggests that the latter is a symplesiomorphy, but with not too high confidence. In any case, the brownish insular or peninsular species chalcurum and inopinatum do not seem to be derived from a single isolation event, and seem to have acquired the more subdued coloration independently. The trend in this genus to lose, not to gain, pronounced sexual dimorphism is better supported by biogeographical and molecular data than the alternate scenario.(Kimball et al. 2001)