SUMMARYMASON, I.J., J.L. McKEAN and M.L. DUDZINSKI. 1984. Geographical variation in the Pheasant CoucalCentropus phasianinus(Latham) and a description of a new subspecies from Timor. Emu 84: 1–15.From traits of sex, age, and nuptial and non-breeding plumages, subspecies ofCentropus phasianinuswithin Australia are described, relating size of wing, tail and bill to latitude. Races in New Guinea are also re-evaluated. Six subspecies ofCentropus phasianinusare recognised: two from Australia(phasianinusin the south-east andmelanurusin the north), three from New Guinea (propinquusin the north,nigricansin the southeast andthierfelderiin the south), and one from Timor (muisubsp. nov.—Mason&McKean). These subspecies are diagnosed by size of wing, tail and bill and plumage colour. In eastern Australia there is an abrupt change in length of wing and tail within the region of the Burdekin Valley, indicating past geographical isolation and secondary contact. New Guinea populations appear to continue the clinal trends in size of south-eastern Australian birds but interposed between them is the larger form across northern Australia. A preliminary outline on relationships ofCentropuswithin the Australo-Papuan region is discussed, based on what is known about their external morphology and ecology. It is suggested thatC. phasianinusentered Australia from New Guinea and entered Timor from Australia.