The Afrotropical Scopaeus paludicola species group (Coleoptera: Staphylinidae: Paederinae), a primitive lineage of the genus

The Afrotropical Scopaeus paludicola species group (Staphylinidae: Paederinae: Lathrobiini) is defined and described. It comprises S. jeanneli Levasseur, 1981 from Kenya and the South African S. insidiosus Fagel, 1973, S. ludificatus Fagel, 1973, S. nigerrimus Cameron, 1945, S. paludicola Cameron, 1945, and S. transvaalensis Fagel, 1973, which are redescribed, and five new species from the Republic of South Africa: S. bikoi sp. nov., S. capensis sp. nov., S. endrodyi sp. nov., S. rectiphallatus sp. nov., S. uhligorum sp. nov.. Lectotypes are designated for S. paludicola Cameron, 1945 and S. p. pallipes Cameron, 1945. The doubtful synonymy of these taxa is discussed. An identification key for the S. paludicola species group is presented, and its distribution is mapped. The S. paludicola species group differs from the current definition of Scopaeus in some characters, but it belongs to the genus according to the presence of the metathoracic/mesofemoral stridulum. The presence of a ventrolongitudinal, membranous split of the aedeagus is considered a derived character of the species group. A midlongitudinal groove of the mesobasisternum is apomorphic for the S. paludicola lineage from southern Africa, which comprises most species of the group. The S. paludicola species group is considered to be a basal lineage of Scopaeus, because it shares ancestral genital characters of the Scopaeina, such as a dorsally membranous aedeagus with a proximal median foramen and a simple sperm pump without the characteristic appendage of the chamber segment of most Scopaeus. Based on the newly recognized characters of the S. paludicola species group and other Scopaeus species, a revised hypothesis on the basal phylogeny of the genus is presented.