Phylogenetic placement of Arrowinini trib.n. within the subfamily Staphylininae (Coleoptera: Staphylinidae), with revision of the relict South African genus Arrowinus and description of its larva

The rove beetle genus Arrowinus, a flightless endemic of South Africa, is revised. Arrowinus phaenomenalis Bernhauer, the type species of the genus, is redescribed based on an examination of type and additional material. Three new species, A. relictussp.n., A. peckorumsp.n. and A. minutussp.n., are described. For all four species, an identification key for adults and larvae is provided, along with available data on their distribution and bionomics. Phylogenetic relationships among the four species of Arrowinus were sought by means of a cladistic analysis. Based on the presumed larvae of A. peckorum and other species of the genus (identified by association with the respective adults), the first larval description for Arrowinus is provided. By means of a cladistic analysis of morphological characters of both adults and larvae, analysed separately and in combination, the phylogenetic relationships of Arrowinus with other members of the subfamily Staphylininae were revealed and are discussed. To facilitate this discussion, current problems of phylogeny and systematics are summarized for all Staphylininae. In agreement with an earlier hypothesis, the analysis confirmed that Arrowinus does not belong to the subtribe Quediina of the tribe Staphylinini (where it has hitherto resided) but constitutes a separate taxon, sister to the tribe Staphylinini, for which a new tribe Arrowinini is established. The analysis provides support for the monophyly of the tribe Staphylinini, the subfamily Staphylininae, and the clade (Staphylininae + Paederinae). Adult and larval identification keys to all tribes of Staphylininae are provided.