Revision of Australian Rheotanytarsus Thienemann & Bause (Diptera&COLFAML; Chironomidae), with emphasis on immature stages

The immature stages of the genus Rheotanytarsus Thienemann & Bause (Diptera: Chironomidae) are abundant, diverse and ecologically significant components of Australian flowing waters. The immature stages (fourth-instar larvae and pupae) of the previously described species R. christinae Glover, R. flabellatus Glover, R. juliae Glover, R. trivittatus (Johannsen) (a new senior synonym of R. johnstoni Glover) and R. underwoodi Glover are described for the first time. Four species are described as new: R. barrengarryensis, sp. nov., R. gloveri, sp. nov., R. oss, sp. nov., and R. petropholeter, sp. nov. (the last based on the distinctive pupal stage alone). Illustrated identification keys are provided to all known adult males, pupae and larvae. Two species previously allocated to Rheotanytarsus on the basis of the female adult alone, R. ogilbyi (Skuse) and R. annulatus Glover, are transferred to the genus Tanytarsus Kieffer following detailed examination of their genitalia. Both taxa remain unrecognised in any other life-history stage. Adults of Australian Rheotanytarsus species emerge over extended periods (perhaps throughout the year), showing seasonal and diurnal variation in time of day of emergence. They tolerate a range of aquatic pollutants, and utilise a wider range of low flow conditions than previously reported.