Recent trawling in the Southern Ocean has yielded individuals of a number of species of the deep sea octopod genus
Thaumeledone.This paper provides the first molecular study of the genus, employing molecular sequences from five mitochondrial (12S rDNA, 16S rDNA, COI, COIII, cytochrome oxidase b) and a single nuclear gene ( rhodopsin) and includes representatives of each of the known Southern Ocean species. Thaumeledone rotunda, believed to be circumpolar in distribution and found in relatively deep water is the sister taxa to T. gunteri, known only from South Georgia. A notable level of sequence variability was evident between a T. peninsulaeindividual recently captured from the Powell Basin, and two T. peninsulaeindividuals captured from the continental slope, north of the South Shetland Islands. This is likely to represent population level intraspecific variation within this species.