Global diversification of coastal <i>Cafius</i> rove beetles (Coleoptera: Staphylinidae) driven by ocean currents since the early Miocene

As our understanding of abiotic factors continues to grow, along with insights into the biological traits of organisms, so too does the sophistication of studies exploring global diversification and spatio-temporal distribution patterns. The global distribution of coastal Cafius rove beetles, combined with the endemic distribution patterns observed in its subclades, suggests repeated colonization of new regions via ocean surface currents, followed by local diversification and speciation. We reached these conclusions by reconstructing the Cafius phylogeny and a time-calibrated Cafius phylogeny, then conducting a spatio-temporal biogeographic analysis. Our study is based on sequences from 10 genetic loci, including six nuclear and four mitochondrial genes (6891 bp). Our findings support the monophyly of Cafius, with an estimated origin in the early Miocene (17.91 Ma) along the coasts of Europe and Australia. From this origin, transoceanic dispersal events led to the colonization of the coasts. These patterns suggest that ancestral Cafius lineages initially migrated to continental coastlines, with subsequent vicariance and in situ speciation. The directionality of these colonization events closely aligns with global ocean surface current patterns and the geological and climatic history of the regions involved. Biological adaptations likely facilitated their survival and subsequent diversification in coastal habitats worldwide.