A Systematic Revision of the Rhytidoponera Impressa Group (Hymenoptera : Formicidae) in Australia and New Guinea.

Abstract

The Rhytidoponera impressa group is revised on the basis of worker ant morphology, supplemented by information from ecological and genetic studies. Five species are recognized, all of which occur in mesic habitats along the east coast of Australia: chalybaea Emery (New South Wales, southern Queensland), confusa, sp. nov. (Victoria, New South Wales, southern Queensland) enigmatica sp. nov. (Sydney region, N.S.W.),impressa Mayr (Queensland) and purpurea Emery (north Queensland, New Guinea). R. purpurea is the most distinct morphologically. Of the remaining species, chalybaea and confusa are exceedingly similar and in some localities can be unequivocably distinguished only on the basis of electrophoretic (allozyme) differences. Biogeographical relationships of the impressa group are discussed in relation to past climatic and vegetational changes.