A REVIEW OF ANDOTYPUS AND AUSTROTYPUS GEN. NOV., RYGMODINE GENERA WITH AN AUSTRAL DISJUNCTION (HYDROPHILIDAE: RYGMODINAE)

The taxonomy and morphology of species related to the genus Andotypus Spangler, 1979 (Coleoptera: Hydrophiloidea: Hydrophilidae: Rygmodinae) are reviewed in detail. Austrotypus gen. nov. is established for A. nothofagi sp. nov. (eastern Australia) and A. peruanus sp. nov. (Peru), both of which share the same morphology of the mouthparts and mesoventrite. The genus Andotypus is found to be endemic to central and sourthern Chile, containing two species: A. ashworthi Spangler, 1979 and A. araucariae sp. nov. Andotypus perezdearcei Moroni, 2000 is found to belong to the genus Dactylosternum Wollaston, 1854 (Hydrophilidae: Sphaeridiinae: Coelostomatini), and is a junior subjective synonym of the introduced species D. abdominale (Fabricius, 1792). Adults of all species of Andotypus and Austrotypus are (re)described in detail and important characters are illustrated. Larval morphology and head chaetotaxy is described and illustrated in detail forAndotypus ashwortivi andAustrotypcs nothofagi, revealing differences in head morphology and abdominal tergites which support the separate status of both genera. The taxonomic position of the genera within the Rygmodinae is briefly discussed, but should be corroborated by formal phylogenetic analysis. We hypothesize that the austral disjunct distribution of Austrotypus as well as current distribution of Andotypus are results of the break-up of Gondwana combined with changes of climate in austral South America, Antarctica and Australia during the Cenozoic. Andotypus and Austrotypus represent an independently evolved lineage of dung-and carrion-associated beetles native to the southern temperate zone, and the fact that their larvae largely resemble those of Sphaeridium Fabricius, 1775 suggests that they may represent a partial ecological analogue of the Old World medium-sized coprophilous hydrophilids of the tribe Sphaeridiini. The syntopical co-occurrence of Austrotypus nothofagi with four similarly colored scarabaeoid dung-inhabiting beetles (Onthophagus syclneyensis Blackburn, 1903, O. arrilla Matthews, 1972, Lepanus ustulatus (Lansberge, 1874) and Liparochrus minus Paulian, 1980) suggests that Austrotypus not hofagi may be a member of a mimetic complex formed by these species.