Geographical variation in the Pheasant Coucal Centropus phasianinus (Latham) and a description of a new subspecies from Timor

Abstract

From traits of sex, age, and nuptial and non-breeding plumages, subspecies of Centropusphasianinus within Australia are described, relating size of wing, tail and bill to latitude. Races in New Guinea are also re-evaluated. Six subspecies of Centropus phasianinus are recognised: two from Australia (phasianinus in the south-east and melanurus in the north), three from New Guinea (propinquus in the north, nigricans in the southeast and thierfelderi in the south), and one from Timor (mui subsp. 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 of Centropus within the Australo-Papuan region is discussed, based on what is known about their external morphology and ecology. It is suggested that C. phasianinus entered Australia from New Guinea and entered Timor from Australia.