The genus Antimerus Fauvel, 1878, endemic to eastern Australia and Tasmania and a phylogenetically enigmatic member of the large rove beetle tribe Staphylinini, is revised. The genus and each of its four previously known species are redescribed, and a lectotype is designated for Antimerus punctipennis Lea, 1906. Five species are described as new: Antimerus metallicus sp. n., A. jamesrodmani sp. n., A. gracilis sp. n., A. bellus sp. n. and A. monteithi sp. n., so that the number of known species in this genus now totals nine. For the first time Antimerus larvae are described, tentatively identified as A. smaragdinus Fauvel, 1878, A. punctipennis and A. metallicus. Available distributional and bionomic data are provided for each species and summarized in the discussion. Adult and larval morphology of Antimerus and its distribution patterns are discussed in the broader context of new data on the evolution of the entire tribe Staphylinini, and with respect to the formation of the Australian fauna of this tribe. The phylogenetic position of Antimerus within Staphylinini remains unresolved pending a targeted formal study. However, a majority of currently available data suggests that it could be a basal member of the recently recovered monophyletic clade of Staphylinini tentatively called “Staphylinini propria”.
