Persistent genetic signatures of historic climatic events in an Antarctic octopus

Repeated cycles of glaciation have had major impacts on the distribution of genetic diversity of the Antarctic marine fauna. During glacial periods, ice cover limited the amount of benthic habitat on the continental shelf. Conversely, more habitat and possibly altered seaways, were available during interglacials when the ice receded and the sea level was higher. We used microsatellites and partial sequences of the mitochondrial cytochrome oxidase c subunit 1 (MT-CO1) gene to examine genetic structure in the direct-developing, endemic Southern Ocean octopod Pareledone turqueti Joubin, 1905 sampled from a broad range of areas that circumvent the Antarctic continent. We find that, unusually for a species with poor dispersal potential, P. turqueti has a circumpolar distribution and is also found off the islands of South Georgia and Shag Rocks. The overriding pattern of spatial genetic structure can be explained by hydrographic (with ocean currents both facilitating and hindering gene flow) ...