Revision of the subgenus Orphnus (Phornus) (Coleoptera, Scarabaeidae, Orphninae)

The Afrotropical subgenus Phornus Paulian, 1948 of the genus Orphnus MacLeay, 1819 is revised and currently comprises six species. Four new species are described: Orphnus renaudi sp. nov., Orphnus valeriae sp. nov., Orphnus ferrierei sp. nov. and Orphnus parastrangulatus sp. nov. The subgenus is characterized by the coarse stridulatory field, sclerotized plate on the second abdominal sternite near plectrum, absence of the pronotal lateral processes in males, rounded apices of the parameres and endophallus without armature, although some of these characters differ in O. giganteus Paulian, 1948. Symphysocery is reported for the first time for members of the Orphninae. In O. giganteus, the majority of specimens have malformed antennomeres. Four of the six species of Phornus are brachypterous and all species except for O. giganteus are known only from males. A key to Phornus species and a map of their localities are provided.