Abai, MR

6th International Congress of DipterologyAustralasian stiletto flies (Diptera: Therevidae): Divergencetime estimates indicate Gondwanan separation, evolutionaryradiations with aridification, and recent dispersalLambkin, C.L. (1), B.M. Wiegmann (2), D.K. Yeates (1), J. Thorne (3), B. Cassel (2) &M. Hauser (4)(1) CSIRO Entomology, Canberra ACT 2601 AUSTRALIA(2) Dept of Entomology, North Carolina State University, Raleigh, NC, 27695 USA(3) Dept of Statistical Genetics, North Carolina State University, Raleigh, NC, 27695,USA(4) California Department of Food & Agriculture, Sacramento, CA 95832-1448, USAWhy are there so many stiletto flies (Therevidae) in Australia? Intensivefield and systematic research over the last decade has revealed a fauna weestimate at 700 species, arranged in three independent lineages; theAgapophytinae, the Taenogera group of genera, and the Anabarhynchusgroup of genera. While the Agapophytinae is endemic to Australasia, theother two lineages also have a few species in Chile or Argentina. Wediscuss the latest divergence time estimates for the Australian Therevidaeand the implications for studies of evolutionary radiations of Australianfauna. Preliminary research showed that Australian therevid divergencetimes correlated with known gondwanan biogeographical events. Recentpaleontological research has provided accurate phylogenetic assignmentsand ages for key fossils required to calibrate the molecular clock. Analysisof a dataset comprising intense taxon samples from the three radiationsshows that while these lineages arose in the late Cretaceous or earlyTertiary, the intense species-level evolutionary diversification did notbegin until the mid Tertiary. At least six Australian genera have radiated inconjunction with the aridification of Australia. The New Caledonian faunaappears to have been a result of recent dispersal from Australia, rather thanGondwana vicariance.Key Words: biogeography, stiletto flies152