Taxonomy of 'Euconnus complex'. Part XVIII. Status of subgenera Palaeoconnus Franz and Heterotetramelus Franz (Coleoptera, Staphylinidae, Scydmaeninae).

Based on examination of type species, the subgenera Palaeoconnus Franz and Heterotetramelus Franz are removed from Euconnus Thomson. Adults of Palaeoconnus have the prosternum bearing a subtriangular prosternal process and their metacoxae are contiguous, which exclude this taxon from Euconnus. Palaeoconnus is transferred to Sciacharis Broun as subgenus and redefined. The lectotype is designated for its type species, Scydmaenus brevipes Sharp. Sciacharis andicola (Franz), previously treated as incertae sedis within Sciacharis, is placed in Palaeoconnus. Heterotetramelus is also excluded from Euconnus, on the basis of the mesoventrite lacking the mesoventral intercoxal process and the contiguous metacoxae. Heterotetramelus stat. n. is elevated to genus rank and redefined, and the lectotype is designated for its type species, Euconnus caledonicus Franz. Moreover, the newly defined Heterotetramelus is reclassified to include four subgenera: Heterotetramelus s. str. (with seven species distributed in New Caledonia), Sciacharoides Jałoszyński, stat. n. (reduced from genus; with three Australian species); Australosciacharoides subgen. n. (with only one Australian species transferred from Sciacharoides); and Tamborinus subgen. n. (also with one Australian species transferred from Sciacharoides).