Revision and molecular phylogeny of the genus Gastrobothrus (Coleoptera: Staphylinidae: Pselaphinae)

We conducted a taxonomic revision of the New Zealand members of Gastrobothrus sensu novo (the former “ Gastrobothrus - group ”) consisting of the genera Eupinogitus Broun, 1921, Gastrobothrus Broun, 1882, and Physobryaxis Hetschko, 1913. Based on the results of a molecular phylogenetic analysis, a new synonymy is established for the following taxa: Gastrobothrus Broun, 1882 (= Eupinogitus Broun, 1921, syn. nov. = Physobryaxis Hetschko, 1913, syn. nov.).

New combinations are proposed as well: Gastrobothrus inflatus, comb. nov. (= Physobryaxis inflatus (Sharp, 1874 )) and Gastrobothrus sulcipennis, comb. nov. (= Eupinogitus sulcipennis Broun, 1921).

The five previously described species are redescribed and 14 new species are described: Gastrobothrus angustus sp. nov., G. biligo sp. nov., G. directus sp. nov., G. giganteus sp. nov., G. grossus sp. nov., G. lunatus sp. nov., G. occultus sp. nov., G. pilosus sp. nov., G. planiventris sp. nov., G. pumilus sp. nov., G. quadrus sp. nov., G. retusus sp. nov., G. spinifer sp. nov., and G. trigonus sp. nov. An identification key to all formally described and unnamed species within the genus and high-resolution images of diagnostic characters for each are provided.