If creatures of the deep with too many tentacles that live in perpetual darkness is not usually your thing, let us tempt you to the dark side with this glorious new species of deep-sea crown jellyfish.
Discovered in the waters off California by Monterey Bay Aquarium Research Institute (MBARI) researchers, meet Atolla reynoldsi, a fabulous scarlet deep-sea alien with 26 to 39 tentacles that resides in the ocean's "midnight zone".
Atolla is a genus of relatively common deep-sea crown jellies and is pretty easy to spot (for those who can see through the inky blackness of the midnight zone, where no sunlight permeates) due to the color of its bell (red actually appears black in the deep sea) and the fact it has one tentacle much longer than the rest. When MBARI researchers first spotted one 15 years ago that didn't have the tell-tale long appendage, however, they were curious.
Now, in a paper published in Animals, they have officially described the large new jelly, naming it A. reynoldsi after the very first volunteer at Monterey Bay Aquarium.
There are at least 10 known species of Atolla found around the world, and most have a single trailing hypertrophied tentacle that can reach up to six times the diameter of the jelly's bell (the umbrella-shaped jelly dome part of the body). Previous research has suggested this is to snag unsuspecting prey – like siphonophores, long string-like creatures, or crustaceans – for a tasty snack. However, after 15 years and thousands of hours of video footage observing at least three Atolla-like jellies without one, researchers came to the conclusion they were looking at at least one, but probably three, new species of Atolla.
Two more are noted in the paper, though there were not enough samples to officially describe them yet.
A. reynoldsi, on the other hand, has been described as being one of the largest in the genus, at around 13 centimeters (5.1 inches) in diameter. It also has an unusual bumpy bell with warty papillae and spiked ridges only seen in one other Atolla. It even has a distinct gut that the researchers described as shaped like a Greek cross.

They also discovered that tentacle number is not a reliable way to identify a species, since A. reynoldsi seems to have anywhere between 26 and 39 tentacles. MBARI researchers have only observed 10 specimens of the new jelly in total, so it's not common, although its deep red color helps it hide in plain sight at depths of 1,013 to 3,189 meters (3,323 to 10,463 feet).
“These remarkable new jellies underscore how much we still have to learn about the deep sea. On just about every dive into the depths of Monterey Bay, we learn something new,” said MBARI Senior Education and Research Specialist and lead author on the paper, George Matsumoto. MBARI has discovered 225 new species in Monterey Bay and beyond over the last 34 years, with no signs of slowing down and at least two more new species waiting in the wings to be confirmed.
“MBARI’s work to understand the ocean is more urgent than ever as the deep sea and the animals that live there face a growing number of threats. We cannot protect life in the deep sea unless we understand it first,” Matsumoto said.