DNA barcoding reveals both cryptic as true circumpolar species in Antarctic Lysianassoidea (Amphipoda)

Recent molecular analyses revealed that several so-called “circum-Antarctic” benthic crustacean species appeared to be a complex of cryptic species with restricted distributions. In this study we used DNA barcoding to detect possible cryptic diversity and to test the circumpolarity of species belonging to the amphipod genus Orchomene sensu lato (superfamily Lysianassoidea). A fragment of the cytochrome c oxidase I gene performed as a powerful barcoding marker for these taxa, showing a clear barcoding gap between intra- and interspecific divergences. In addition, DNA barcoding served as a quick survey for species diversity in this group. While in some species a genetic homogeneity was found among specimens from remote sampling sites, we detected genetically divergent, cryptic taxa in other species. Based on these observations, our current view on the species richness and distribution of the Antarctic Lysianassoidea may have to be modified. As polar regions are more affected by climate change than others, biodiversity assessment studies are of particular importance since they may serve as a basis for monitoring and conservational efforts.