Biogeography and classification of New Guinean Colymbetini (Coleoptera:Dytiscidae:Colymbetinae)

Abstract

The systematics of New Guinean Colymbetini is revised. All of the species aremontane and/or subalpine, and include:Carabdytes upin Balke, Hendrich & Wewalka, 1992;Rhantus suturalis (MacLeay, 1825)s.l.; R. papuanus Balfour-Browne,1939; and R. ekari Balke & Hendrich, 1992a. Thefollowing new species are described: R. anggi, sp. nov.;R. bacchusi, sp. nov.; R. dani,sp. nov.; R. kakapupu, sp. nov.;R. riedeli, sp. nov.; andR. supranubicus, sp. nov.Rhantus neoguinensis Guéorguiev & Rocchi,1993 is a junior subjective synonym of R. suturalis s.l.All New Guinean Rhantus Dejean, 1833 belong to themonophyletic R. suturalis-group. Within that group,Rhantus simulans Régimbart, 1908 (southwestAustralia),R. dani, R. suturalis,R. ekari and R. kakapupu form amonophyletic subgroup; the latter two are sister-species. TheR. suturalis-group is suggested to be of Holarcticorigin. Possible scenarios that may explain the biogeographical history ofthis tribe in the Indo-Australian region are discussed. No evidence was foundfor monophyly of New Guinean Rhantus. Thebiogeographical history of Carabdytes upin remainsenigmatic. New Guinean Rhantus inhabit swamps atlakeshores, ponds and ditches, while C. upin Balkeet al., 1992 is a rheobiont. A checklist of worldspecies of the R. suturalis-group is provided.