Taxonomic revision of the Ethiopian genus Canthyporus (Coleoptera Dytiscidae)

Abstract

The genus <em>Canthyporus</em> Zimmermann, 1919, is revised. A total of 35 species are recognized, all of them distributed within the Ethiopian Region, and with a centre of diversity in the South African Western Cape province. Descriptions of all species are given together with illustrations of habitus and male and female genitalia. A key to species (males), distribution maps, and ecological information are provided. Four new species are described from South Africa: <em>Canthyporus aenigmaticus</em> n.sp., <em>C</em>. <em>nimius</em> n.sp., <em>C. turneri</em> n.sp., and <em>C. wewalkai</em> n.sp. The species <em>C. congener</em> Omer-Cooper, 1956, is regarded as valid and not as a junior synonym of<em> C. canthydroides</em> (Régimbart, 1895). Lectotypes are designated for the following ten names:<em> C. alvei</em> Omer-Cooper, 1965, <em>C. consuetus </em>Omer-Cooper, 1965, <em>C. latus</em> Omer-Cooper, 1965, <em>C. lowryi </em>Omer-Cooper, 1965, <em>C. nebulosus</em> Omer-Cooper, 1965, <em>C. similator</em> Zimmermann, 1923, <em>C. simulator</em> Guignot, 1959, <em>C. testaceus</em> Zimmermann, 1923, <em>Hydroporus collaris</em> Boheman, 1848, and <em>Hydroporus hottentottus</em> Gemminger & Harold, 1868. A parsimony analysis based on 32 morphological characters found 28 shortest trees. Monophyly of the genus <em>Canthyporus</em> is supported mainly by the presence of an anterior ligula on the ventral side of the elytron. Four species groups are recognized within the genus: (1) <em>canthydroides</em> group, including ten species in Namibia and South Africa; (2) <em>exilis</em> group, including four species in Lesotho and South Africa; (3) <em>hottentottus</em> group, including 18 species from the Democratic Republic of the Congo, Ethiopia, Kenya, Lesotho, Madagascar, South Africa, Swaziland, Tanzania, and Zimbabwe; and (4) <em>lateralis</em> group, including three species from South Africa.