Giant Pacific Octopuses (GPO) aka Enteroctopus dofleini are fascinating marine creatures. They are known to be the largest among all octopuses but turns out, we don't know them too well.

A series of observations have revealed that two different species have been hiding under GPO's moniker for years — one is the giant Pacific octopus most of us are familiar with, while other is a "frilled giant Pacific octopus" that so far has been a previously unknown species.

Though scientists have long suspected that two different species existed, there was no visual confirmation until Professor David Scheel and Nathan Hollenbeck from Alaska Pacific University used shrimp fishing pots as a snare to catch these octopuses.

On occasions, along with shrimps, octopuses also climb into these pots and that's exactly what helped the researchers collect 21 octopuses.

Studying visual features of these creatures, the team discovered that 14 of the octopuses were GPOs, while the remaining seven had a distinct frill along the length of their bodies and belonged to a different species, according to Earther. The previously unobserved creatures even had weird protuberances under their eyes, much like eyelashes, and two white spots on the head. In contrast, giant Pacific octopus only had one such spot.

In terms of weight, the heaviest of the new octopuses was a female weighing around 2.5kg, while the familiar adult GPOs are known to weigh around 33kg, which could go up to 70kg.

To confirm the differences, the team even conducted a series of DNA tests. For this, they swiped the octopuses' skin with a cotton swab and collected cells that make up the tissues that line the cavities and surfaces of body organs. The tests revealed that these seven creatures belonged to a genetically different species and were distinct from giant Pacific octopuses.

Though frilled giant Pacific octopuses are yet to be described and officially named, the new species, which we now know had been hiding in plain sight, could bring about a change in the population of GPOs. So far, frilled GPOs have been spotted in waters ranging from Juneau to the Bering Sea, but further studies could give us new and better insights into the habitat as well as the population of these creatures.

Giant Pacific octopuses, on the other side, have been spotted all over Northern Pacific and chances are those groups may also have included their frilled siblings.

The study on the octopuses has been published in a paper that appeared in the November edition of American Malacological Bulletin.