Data from: 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) and bathymetric features. The Antarctic Peninsula region displays a
complex population structure, consistent with its varied topographic and
oceanographic influences. Genetic similarities between the Ross and
Weddell Seas, however, are interpreted as a persistent historic genetic
signature of connectivity during the hypothesized Pleistocene Western
Antarctic Ice Sheet collapses. A calibrated molecular clock indicates two
major lineages within P. turqueti, a continental lineage and a
subAntarctic lineage, that diverged in the mid-Pliocene with no subsequent
gene flow. Both lineages survived subsequent major glacial cycles. Our
data are indicative of potential refugia around the Antarctic continent
within the Ross Sea, Weddell Sea and off Adélie Land, with mean age of
mtDNA diversity within these main continental lineages coinciding with
Pleistocene glacial cycles.