Systematics of Nanexila Winterton & Irwin, gen. nov. (Diptera:Therevidae) from Australia

Abstract

Nanexila Winterton & Irwin, gen. nov. is describedand figured from Australia. This genus of typically small, slender flies isdivided into three species-groups following cladistic analysis. The previouslyunplaced N. manni (Hardy) comb. nov. is redescribed inthe Nanexilamanni species-group, along with four newspecies: N. armeniacum,N. carminata, N. furcata andN. nana. Nanexila ruficornis (Macquart) comb. nov. isredescribed in the Nanexila palassa species-group, alongwith ten new species: N. argentiquadris,N. cylomelasma, N. danielsi,N. ligula, N. lignyos,N. livea, N. palassa,N. spilotis, N. variabilis, andN. vittata. Four new species are described in theNanexila atricostalis species-group:N. atricostalis, N. aureilineata,N. intermedia, and N. paradoxa.The twenty Nanexila species and five outgroup specieswere compared across 167 states in 71 characters. A cladistic analysis wasconducted and the phylogenetic relationships of Nanexiladiscussed. Nanexila is endemic to Australia, with alargely southern distribution. Only N. argentiquadrisand N. cylomelasma are known from northern Australia.Adult Nanexila have been collected between August andApril, with the peak period of activity for most species during October andNovember. The duration of adult activity is related to latitude, with northernspecies active for longer periods than southern species.