Flightless beetles crossed the Pacific Ocean: phylogeny and biogeography of the intertidal genus Diaulota Casey (Coleoptera: Staphylinidae: Aleocharinae).

This article focuses on the phylogenetic and biogeographic history of the intertidal rove beetle genus Diaulota, which inhabits the Pacific coasts of the Northern Hemisphere. Using molecular data and multiple phylogenetic methods, the study supports Diaulota as a monophyletic group originating along the East Asian coast (Korea and Japan), with its current North Pacific distribution shaped by both dispersal and vicariance events. Most species appear to have colonized the northeastern Pacific via stepwise dispersal following ocean currents from the northwestern Pacific, while one lineage likely dispersed directly across the Pacific Ocean, possibly via rafting on marine debris. The findings highlight the role of sea surface currents and coastal habitat adaptations in the evolutionary diversification of Diaulota and suggest that both dispersal and vicariance contributed equally to their biogeographical patterns.