It turned up almost by accident, a tiny blue octopus moving across the seafloor nearly 1,800 metres below the Galápagos.

Scientists have now identified the animal as a new species, Microeledone galapagensis, in a study published in Zootaxa.

The octopus was first spotted during a 2015 deep-sea expedition aboard the exploration vessel E/V Nautilus, carried out with the Charles Darwin Foundation and the Galápagos National Park Directorate.

Researchers were using a remotely operated underwater vehicle to investigate the seafloor near Darwin Island, at the northern edge of the Galápagos archipelago, when they saw the octopus near an underwater mountain about 1,773 metres below the surface.

The expedition audio captured the team’s reaction: “He’s tiny!” “It’s blue!”

Using the vehicle, the team collected one specimen and recorded video of two others that appeared to be the same species.

Back in the Galápagos, researchers took dozens of deep-sea specimens to the Charles Darwin Research Station for examination. The blue octopus, about the size of a golf ball, looked unlike any known species.

Researchers contacted octopus expert Janet Voight and sent her photographs of the animal.

“Right away, I knew it was something really special,” said Voight, curator emerita of invertebrates at the Field Museum in Chicago and lead author of the study. “I’d never seen anything like it.”

The specimen was preserved in alcohol and formalin and shipped to Chicago, where Voight examined it at the Field Museum.

She said describing a new octopus species usually means dissecting the animal to study features including the mouth, beak and teeth, but the team had only one confirmed specimen.

“When you describe a new species of octopus, you have to look at all the parts, including the mouth, the beak, and the teeth. And to see those things, you have to cut the specimen open. We only had the one specimen, so I didn’t want to take it apart,” Voight said.

Instead, the researchers used micro CT scans to study the octopus without cutting into it.

Stephanie Smith, manager of the Field Museum’s X-ray computed tomography laboratory and a co-author of the paper, helped create the scans.

“Because CT imaging is non-destructive, it’s especially important for type specimens like this one. And that’s great for me because people are often bringing me these incredibly rare and stunningly beautiful specimens that I get the privilege of virtually opening up,” Smith said. “There’s nothing like spending the day looking at something no other human has ever seen.”

According to the Field Museum, the scans combined thousands of X-ray images into a 3D model that showed the octopus’s exterior and internal anatomy, including internal organs and mouth structures.

“What really struck me was that the scan of the little octopus revealed so much information on its internal organ systems, usually, soft-part imaging using micro CT requires the use of heavy-metal-based contrast agents whose use would not be desirable with such a rare specimen. This made the 3D modeling of relevant organs really an easy task,” said Alexander Ziegler, a researcher at the University of Bonn in Germany and senior author of the paper.

Voight said the find was also a first in her own career after more than 40 years studying octopus evolution.

“These are little octopuses that live in the deep sea, and hardly anybody on Earth has ever gotten to see them. I just feel lucky that I got to work with them,” she said.

Salome Buglass, a marine scientist at the University of California of Los Angeles, former researcher at the Charles Darwin Foundation and a co-author of the paper, said the specimen stood out while the team sorted material from the expedition.

“When we were sorting through dozens of specimens collected during the expedition, this tiny blue octopus fascinated us,” Buglass said. “There was something unusual about it, so we went out of our way to find the right person to help us identify what it was.”

“Getting the specimen to Janet was a long process, but one I would gladly repeat if it means getting to know the most precious parts of our ocean just a little bit better. Discoveries like these remind us how much of the deep ocean in Galápagos remains unexplored. Every new species helps us better understand these hidden ecosystems and why protecting them matters.”

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