An adult individual of Microeledone galapagensis is so tiny that it could fit in the palm of your hand. Its small size might be an evolutionary adaptation.
Charles Darwin Foundation
Nearly 1,800 meters beneath the surface of the Pacific, a remotely operated submersible was creeping along the slope of a Galápagos seamount when its camera caught a tiny, dark blue octopus perched in the sediment — an animal no human had seen before.
Researchers have named the species Microeledone galapagensis. Small enough to fit in the palm of your hand, it is also fully grown — a combination that may help it reproduce faster than larger relatives, biologist Janet Voight and colleagues report in the May 25 Zootaxa.
The encounter happened in 2015, during a 10-day research expedition. “It’s like those little plushies that kids put on their backpacks,” one of the researchers said in a recording of the dive.
After the submersible brought the roughly 10-centimeter-long octopus to the surface, the team shipped it to the Field Museum in Chicago. There, scientists analyzed it using micro-computed tomography, building 3-D models of organ systems used to tell species apart. It’s the first octopus species described using CT scanning alone, which let researchers confirm the new species without dissection. That mattered: Despite seeing four likely members of the species during their expedition, the team captured only one.
The individual isn’t a juvenile — it’s a fully grown adult with a complete set of arm suckers and 13 eggs in its ovaries. Its small size may be an adaptation. A juvenile-sized body “could increase the rate of reproduction” by shortening the time from hatching to first eggs, says Voight, a curator at the Field Museum. Being small might also help it escape predators.
Its short, stubby arms might be built for digging, Voight says. That foraging style may explain its coloration — a pale body with dark blue arms and webbing. “When the octopus is digging in the sediment for prey, she may stimulate those prey items to bioluminescence,” she says. The dark webbing might shield that light from predators while the octopus eats. After swallowing, pigment cells inside the body could block any glow from within.
Only one other species in the genus is known, found in waters off New Caledonia in the South Pacific — suggesting other species might live between the two areas.
“The Pacific Ocean is unimaginably immense, and every part of it contains animal life from the surface to the seafloor,” Voight says. “This specimen highlights that unknown diversity.”
