S. Mahunka szerk.: Folia Entomologica Hungarica 57. (Budapest, 1996)

The originally included species in Hydroporus Clairville, 1806 now are relegated to the following genera: — Yola Des Gozis, 1886 (Dytiscus bicarinatus); — Hydroporus auct. (D. fuscidus, as a junior subjective synonym of D. ater Forster, 1771); — Hyphydrus Illiger, 1802 (D. gibbus, as a junior subjective synonym of D. ovatus Linnaeus, 1761); — Coelambus Thomson, 1860 (D. ovalis, as a junior subjective synonym of D. impressopunctatus Schaller, 1783); — Hygrotus Stephens, 1828 (D. parvulus, as a junior subjective synonym of D. inaequalis Fabricius, 1776); — Hydrocoptus Motschulsky, 1853 (D. sexpustulatus, as a junior subjective synonym of D. palustris Linnaeus, 1761). I designate Dytiscus fuscidus Schrank, 1781 as the type of the genus Hydroporus Clairville, 1806. This does not affect the present usage of this generic name. The following new genera are described for the species Hydroporus angustatus Sturm, 1835 and H. minutissimus Germar, 1824, respectively, as well as for their congeners. Schizoporus gen. n. Type species: Hydroporus angustatus Sturm, 1835 (present designation) — Body elongate-oval, somewhat flattened dorsally. Colouring more or less uniformly pitchblack, brown or reddish brown. Clypeus truncate, barely emarginate and not bordered anteriorly. Eyes well developed. Last segment of labial palpi truncate apically, barely emarginate at tip. Pronotum without either submarginal or latero-basal stria. Lateral border of pronotum vanishing or absent. Prosternai process lanceolate, narrow, subcarinate, strongly compressed laterally. Pronoto-elytral angle more or less distinct. Scutellum hidden. Elytra without impressed discal striae and without distinct preapical indentation. Elytral punctuation more or less distinct; surface with short, sparse, indistinct pubescence. Elytral margin (in lateral view) distinctly arched at shoulder. Epipleura broad at base, abruptly narrowed at the middle, hence narrow to apex, without a distinct basal cavity and without a diagonal carina crossing near base. Metacoxal line double. Metacoxal processes not separated from each other at apex, transversely truncate, not emarginate apically; common posterior margin of processes subrectilinear, not projecting medially. Pro- and mesotarsi pseudotetramerous. Segment III of protarsi at least twice as long as segment II. Protarsi of male with barely curved, elongate claws fairly different in size; both claws bifid, deeply incised at tip. Posterior (apical) margin of first four segments of metatarsi transversely straight, without natatory hairs. Parameres with an unciform apex; penis anomalous. Calliporus gen. n. Type species: Hydroporus minutissimus Germar, 1824 (present designation) — Body elongate-oval, fairly parallel-sided, somewhat flattened dorsally. Colouring fuliginous or reddish brown; elytra either with obsolete paler marks or with a maculate colour pattern, variegate, somewhat obsoletely delimited. Head with transverse cervical line; clypeus truncate, barely emarginate and not bordered anteriorly. Eyes well developed. Pronotum