Are subcortical rove beetles truly Holarctic? An integrative taxonomic revision of north temperate Quedionuchus (Coleoptera: Staphylinidae: Staphylininae)

The recognition of Holarctic species, those shared between Nearctic and Palaearctic regions, often implies continuous or recent events of gene flow across the 85-km-wide Bering Strait between Alaska and Russia. During the Pleistocene (2.8–0.012 Mya), the Bering land bridge has provided frequent episodes of continuous, tundra habitat across this barrier, while the taiga forests of the northern hemisphere has been separated for much longer, at...