A REVISION OF THE AGABUS-CHALCONATUS-GROUP AND ERICHSONI-GROUPS (COLEOPTERA, DYTISCIDAE), WITH A PROPOSED PHYLOGENY

The Holarctic chalconatus- and erichsoni-groups, with 19 and three spe cies respectively, are revised. The following seven new species are de scribed: Agabus balkei from Siberia, Agabus jaechi from Turkey, Agabus larsoni from Canada, Agabus lenkoranensis from Azerbaijan, Agabus ped erzanii from Italy, Agabus samokovi from Bulgaria, and Agabus wewalkai from Turkey. Lectotypes are designated for the following nominal spec ies: Dytiscus chalconatus Panzer, 1796, Dytiscus nigroaeneus Marsham, 1802, Colymbetes montanus Stephens, 1828, Agabus neglectus Erichson, 1 837, Agabus subtilis Erichson, 1837, Agabus gagates Aube, 1838, Agabus altaicus Gebler, 1848, Agabus erichsoni Gemminger & Harold, 1868, Gau rodytes lutosus Crotch, 1873, Agabus fuscoaenescens Regimbart, 1877, A gabus aenescens Poppius, 1905, Agabus satunini Zaitzev, 1913, and Agab us melanocornis Zimmermann, 1915. The following new synonyms are estab lished: Agabus altaicus Gebler, 1848 = Agabus subtilis Erichson, 1837; Agabus melanocornis Zimmermann, 1915 = Colymbetes montanus Stephens, 1828; Gaurodytes bulgaricus Csiki, 1943 = Dytiscus conspersus Marsham, 1802; Agabus skiathos Hinterseher, 1981 = A gabus pseudoneglectus Fra nciscolo, 1972; and Agabus maestroae Fresneda & Hernando, 1987 = Agabu s albarracinensis Fery, 1986. Agabus aenescens Poppius, 1905, and A. s atunini Zaitzev, 1913, are recognized as valid species (sp. rev.). The chalconatus-group is divided into four subgroups and the phylogeny of the group is reconstructed. The relationships of the chalconatus- and erichsoni-groups with other Agabus species-groups and with Ilybius Er ichson are discussed.