Giant Pacific octopus (Enteroctopus dofleini) Image: Colby Stopa, Flickr

Scientists have long suspected that the largest known octopus may actually be more than one species — and now new research confirms the theory.

The giant Pacific octopus, weighing in at more than 150 pounds, inhabits a huge range of the northern Pacific, spanning from southern California up to Alaska. Fishermen collect them regularly as by-catch in shrimp pots and have probably noticed differences in their appearance for ages, but scientists have only recently singled them out for observation.

To verify whether there were actually more than one species, Nate Hollenbeck and Prof. David Scheel based out of Alaska Pacific University collected 21 octopuses that were by-catch in shrimp pots from Western Prince William Sound, Alaska. Seven of them appeared visually distinct from the rest and coupled with DNA samples serve as the morphological basis for an entirely new species.

Image: David Scheel

This new species of giant Pacific octopus boasts a unique frilly ridge on its mantle and frilly fringing around its eyes. Both of these characteristics attribute to its identification as the ‘frilled giant Pacific octopus’. In addition to frills, this new species has two distinctive white marks on its head, while the more commonly known giant Pacific octopus has only one.

The finding isn’t a huge surprise but definitely sheds some light on these behemoth Pacific cephalopods. Who knows how many other new species of these giant octopuses additional research could uncover? The newly-identified octopus has been described in the American Malacological Bulletin.