Revision of Hemiquedius Casey (Staphylinidae, Staphylininae) and a review of beetles dependent on beavers and muskrats in North America

Baltic amber Staphylinini (Coleoptera: Staphylinidae: Staphylininae): a rove beetle fauna on the eve of our modern climate

Cenozoic climate cooling, particularly during the Eocene, has drastically shaped modern biological assemblages through a shift from an equable greenhouse to a polarized icehouse. Present-day Europe lies in a highly seasonal and temperate area that strongly embodies this modern icehouse climate. Baltic amber provides a Middle Eocene snapshot of the European fauna before this large-scale change. Here, we focused on the rove beetle tribe Staphylinini and conducted a comprehensive phylogenetic study of all known Baltic amber fossils in a total-evidence phylogenetic framework that integrates morphology with molecular data from six gene fragments. Based on our well-resolved topology, we propose the following: †Baltognathina subtrib. nov., Afroquediina subtrib. nov., Antimerina subtrib. nov., †Baltognathus aenigmaticus gen. et sp. nov., †Eolophorus gen. nov., †Laevisaurus robustus and †Laevisaurus gracilis gen. et spp. nov., †Hemiquedius europaeus sp. nov. and †Bolitogyrus fragmentus sp. nov. †Quedius cretaceus is placed as junior synonym of †Cretoquedius infractus. The earliest definitive fossils of Quediina are reported herein from the Eocene. The Staphylinini fauna of Middle Eocene Europe combined thermophilic, freeze-intolerant lineages with freeze-tolerant, temperate lineages and, unlike most other staphylinid or beetle lineages, all have since become extinct in the Palaearctic region.