Graneledone Octopus (Graneledone boreopacifica)
The largest octopus observed at Axial Seamount, Graneledone boreopacifica, is very curious and fairly common on the lava rocks and at hydrothermal vent fields. It is not unique to Axial, as it is found in other Pacific deep sea environments. At Axial, these octopods seem to be attracted to the abundant vent fauna on which they prey. The octopus may also use the hard lava rock substrate found at Axial for laying their eggs.
Specimens off the Oregon coast have been measured at 43 cm (17 in), though Axial specimens are estimated at less than 40 cm.
References:
http://www.pmel.noaa.gov/eoi/nemo/explorer/bio_gallery/biogallery-Info.00006.html http://biostor.org/reference/15
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=58843&fileId=S0952836900000078