Data from: Connectivity, small islands and large distances: the Cellana strigilis limpet complex in the Southern Ocean.

The Southern Ocean contains some of the most isolated islands on Earth and
fundamental questions remain regarding their colonisation and the
connectivity of their coastal biotas. Here we conduct a genetic
investigation of the Cellana strigilis (limpet) complex that was
originally classified based on morphological characters into six
subspecies, five of which are endemic to the New Zealand (NZ) subantarctic
and Chatham islands (44° to 52° S). Previous genetic analyses of C.
strigilis from six of the seven island groups revealed two lineages with
little or no within-lineage variation. We analysed C. strigilis samples
from all seven island groups using two mitochondrial (COI and 16S), one
nuclear (ATPase ) and randomly amplified polymorphic DNA markers (RAPDs),
and confirmed the existence of two distinct lineages. We also detected
pronounced genetic structuring within each lineage, with limpets from each
island having their own genetic identity. These results are strikingly
congruent with those recently reported for the southern bull kelp
Durvillea antarctica, in which the NZ subantarctic and Chatham islands
were proposed as refugia during the Last Glacial Maximum. Given the likely
absence of larval dispersal among the islands, limpet rafting on kelp most
probably explains the observed phylogeographic structure. Island-specific
genetic identities and the paucity of shared haplotypes suggest that a
small number of isolated colonisation events have occurred within each
lineage are characterised by little or no genetic connectivity and
therefore very high (southwest group) or total (northeast group)
self-recruitment.