On the lookout for octopuses

Five species found on Southern French Polynesia expedition!

To find particular invertebrates, you sometimes need to be on particular lookout for them. With an interest in cephalopods (squid, cuttlefish and octopus) I was looking for them on the French Polynesia trip. Could we find a new species as we had done on the previous Kermadecs expedition? I was quick to let the other team members know and we were rewarded by finding a total of six octopus specimens belonging to five species.

In fact, to my chagrin, it was mostly the other team members that did the finding! (I like to think that there is a large lump of luck involved!) Three octopuses were found by members of the ‘fish’ dive team, who collected any interesting invertebrates they came across while fish-collecting.

The species identifications will be confirmed when the specimens return to the Australian Museum in late January 2015. As with most other invertebrates, the identifications need to be done back in the lab where we have access to microscopes and all-important published literature.

In the meantime, some tissue samples from each species that were hand-carried home have been sent to my colleague Jan Strugnell at La Trobe University in Melbourne to compare with DNA sequences obtained with those from already known species.

Prior to our trip, a recently published inventory of French Polynesian marine molluscs included only one species of octopus, Octopus cyanea Gray, 1849 from the Austral Islands and none from the Gambier group of islands (although others could be lurking among museum collections). The species that we collected may represent new records, confirm old published records, or may possibly include new species. Time will tell.

More information:

Tröndle, J., and Boutet, M. Inventory of Marine Molluscs of French Polynesia. Atoll Research Bulletin No. 570. National Museum of Natural History: Smithsonian Institution: Washington DC, USA.

Jereb, P., Roper, C. F. E., Norman, M. D., and Finn, J. K. (eds) (2014). Cephalopods of the world. An annotated and illustrated catalogue of cephalopod species known to date. Volume 3. Octopods and Vampire Squids. FAO Species Catalogue for Fishery Purposes. No. 4, Vol. 3. Rome, FAO. 2014. 370 p. 11 colour plates.