Abai, MR

6th International Congress of DipterologyBiogeographic Patterns in southwest PacificDolichopodidae: New Caledonia, Fiji, and AustraliaBickel, D.J.Australian Museum, 6 College Street, Sydney, NSW 2010 Australiadan.bickel@austmus.gov.auNew Caledonia harbours a rich endemic biota and is considered to be afragment of the ancient Gondwanan supercontinent. Two genera ofDolichopodidae (Medeterinae), Atlatlia and a new genus are sister taxaknown only from Australia and New Caledonia. In Australia both display atemperate southern distribution often associated with Gondwanan taxa,while in New Caledonia, they occur above 500 m. These two genera haveradiated on both landmasses, but are unknown from New Zealand andMelanesia. Two other genera, Antyx and Kowmungia occur only inrainforests of New South Wales, Queensland, and New Caledonia.The Australia and New Caledonia pattern suggests a vicariant Gondwanandistribution as these taxa are unlikely to have dispersed between Australiaand New Caledonia. Were these genera once widely distributed in easternGondwana? The absence of these genera from New Zealand is puzzling.However, during the Tertiary, New Zealand underwent major climacticand tectonically induced extinction events, losing much of its ancestralflora, and probably associated insects as well.As well, New Caledonia has undergone a remarkable radiation in thesubfamily Sciapodinae, with some 75 known species, mostly in the generaLapita and Parentia. These two genera are now known to occur in Fiji. Aswell, Fiji has Sciapodinae of Austro-Papuan affinity, possibly derived fromthe west via “stepping stone” dispersal. Do the Fijian Sciapodinaerepresent a composite of both Gondwanan and Papuan biogeographicorigins?Key Words: biogeography, Dolichopodidae, New Caledonia, Fiji, Pacific22