The Hydroporini (Coleoptera : Dytiscidae : Hydroporinae) of New Guinea: Systematics, distribution and origin of the fauna

Abstract

Only one species of Hydroporini, Megaporus piceatus (RCgimbart, 1892), has been known from New Guinea. M. piceatus is very similar to the Australian M. ruficeps (Sharp, 1882) and study of additional material is neccessary to determine its status. Chostonectes maai, sp. nov., is described from Papua New Guinea. Its sister-species is the Australian C. gigas (Boheman, 1858). The classification of the genera Megaporus Brinck, 1943, and Chostonectes Sharp, 1882, is discussed, and autapomorphies for both groups are suggested. The following species of Hydroporini are reported from New Guinea for the first time: Megaporus sp., Antiporus sp., and Sternoprisccts hansardi (Clark, 1862). A total of five Hydroporini species is now known from New Guinea. All are Australian, or of Australian origin. The New Guinean Hydroporini are not a monophyletic group. The factors delimiting the distribution of Hydroporini in New Guinea are climate and perhaps also vegetation. Australian Hydroporini are adapted to a seasonal climate and most of them also to open forests/woodland.