Lucy [she/faer]

From the photo alone, the octopus appeared to belong to the genus Thaumelodone, a variety of small, squat octopus found in the deep waters of the southern hemisphere.

At first, there was evidence that the animal was indeed part of the Thaumelodone genus. It had a zigzag pattern of suckers on its arms, which is a distinctly Thaumelodone feature. It also had no ink sac—consistent with a Thaumelodone, since in the darkness of the deep ocean, predators can’t see their prey anyway, so a defensive cloud of ink serves no protective function.

But there were multiple differences too. First there was the funnel organ. Octopuses can move at high speed by sucking water into an interior funnel and squirting it out like air escaping from a balloon. Inside the funnel of a Thaumelodone octopus is a small saliva gland, but in this case the gland was comparatively huge, wrapping its way around the entire interior of the funnel.

Then there was the texture. Thaumelodone octopuses are covered with small bumps, or papillae, but the little blue octopus was smooth. There was, too, the matter of the animal’s teeth—or tooth. Thaumelodone typically have seven teeth, but the specimen had just one large one. Finally came the color. The typical Thaumelodone is a shade of maroon. This one—while appearing blue under the light of an underwater camera—was actually white or even clear on top and purple on the bottom.

The verdict: the “blue” octopus did not fit at all in the Thaumelodone group, but rather in the Microeledone, a related deep-water genus—and it was reclassified accordingly.