Abai, MR

6th International Congress of DipterologyBiogeography and phylogeny of marine dolichopodid flies inthe Hawaiian Islands (Diptera, Dolichopodidae)Masunaga, K. (1) & T. Saigusa (2)(1) Lake Biwa Museum, Oroshimo 1091, Kusatsu, Shiga 525-0001, Japan(2) 7-4-12, Baikoen, 2-chome, Chuo-ku, Fukuoka 810-0035, JapanAmong dolichopodid flies, which have their greatest diversity near freshwater, one group lives exclusively on rocky (or coral) seashores. Becausethese marine-shore dolichopodids are confined to a linear habitat, thedistributional ranges of species of this group can easily be represented aslines, instead of areas as is done for inland dwellers. This property is one ofthe exceptional merits of this group for studying biogeography. Weinvestigated six of the main Hawaiian Islands (Hawai’i, Maui, Lanai,Molokai, Oahu, Kauai) to characterize the fauna and clarify the origin ofthe Hawaiian species. We found the only previously recorded Hawaiiandolichopodid species, Conchopus acrosticalis Parent, 1938 (which has alsobeen assigned to Thambemyia Oldroyd, 1956), and five undescribedspecies also belonging to the genus Conchopus Takagi. Only species ofthis genus appear to be distributed in the Hawaiian Islands. Other generadistributed in surrounding Pacific areas, such as Cymatopus Kertész (pantropical),Paraphylosylus Becker (west coast of North America), andAcymatopus Takagi (East Asia) were not found there. We attempted toclarify the phylogenic position and origin of the Hawaiian species ofConchopus by contructing a molecular phylogenetic tree based on mtDNAND5 gene sequence data. Immigration of this group into the HawaiianIslands probably took place on two occasions. The Hawaiian species proveto be the sister-group of the rectus-group of the genus Conchopus, with noimmediate relation to species of Thambemyia.Key Words: Dolichopodidae, Conchopus, Hawaiian Islands, ND5 gene,biogeography158