The distribution of octopuses of Graneledone (Cephalopoda: Octopodidae) in reference to deep-sea features

Although deep-sea hydrothermal vents are renowned for having many apparently endemic taxa, normal deep-sea taxa also occur at vents. These opportunistic taxa have been hypothesized to tolerate these physiologically stressful habitats due to pre-adaptation to low oxygen conditions. Octopuses of the deep-sea genus Graneledone, likely a monophyletic group, appear to be one such taxon as they occur at several East Pacific hydrothermal vents. To further our knowledge of this genus and of other taxa opportunistic at chemosynthetic habitats, collection localities of these octopuses north of 40 degreesS were verified and whether features such as vents, cold seeps, tectonic activity or hydrocarbon deposits were present near the collection localities was determined. Hydrothermal vents, cold seeps or hydrocarbon deposits lie within one degree of 17 of the 24 localities confirmed north of 40 degreesS. This distribution suggests that the octopuses routinely occur in low oxygen habitats, potentially due to a pre-adaptation, a hypothesis that will require a species-level phylogeny for the genus. Low oxygen habitats offer opportunists increased prey biomass and possibly reduced predation rates. In addition, several of these areas offer hard substrata essential for egg attachment and brooding by females of Graneledone.