Amurodytes belovi nov.gen. et nov.sp. from eastern Russia (Coleoptera, Dytiscidae, Hydroporinae)

A b s t r a c t: Amurodytes belovi nov.sp. of the family Dytiscidae is described from the Zeya Nature Reserve in the Far East of Russia – the type locality – and the Bolshoy Amalat River in Buryatia, East Siberia, with a distance of about 900 km between them. It belongs to the Deronectes-group of genera ("Deronectina") (Hydroporini) and at first glance resembles some species of Oreodytes SEIDLITZ 1887. However, it cannot be placed in any known genus of the Deronectina, because a unique combination of characters distinguishes it from all the other species of the tribe, and therefore it is described in a new genus. The most prominent features of the species are the following: cordiform pronotum, broadly exposed interlaminary bridge of metacoxae, and parallel metacoxal lines; both sexes with most antennomeres flattened ventrally, in males even semicircular in cross-section; males with broadly expanded protibiae, without sucker cups on pro- and mesotarsomeres, and with unusually narrow distal portion of the median lobe of the aedeagus. The hind wings of all specimens studied are extremely reduced and at least these specimens were certainly incapable of flight (brachypterous). The habitus, the genitalia and some other structures of the new species are illustrated, the systematic position of the new genus is broadly discussed and a modified key to genera of the Deronectina – including Amurodytes nov.gen. and Oreodytes – is provided. K e y w o r d s: Coleoptera, Dytiscidae, Hydroporinae, Deronectina, Amurodytes, new genus, new species, brachypterous, description, key to genera.