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The Inertia

The ocean is a crazy place, isn’t it? It covers some 70 percent of the Earth, yet there’s so much we don’t know about it. So many places unexplored. So many crazy creatures yet to be discovered. And researchers at the Monterey Bay Aquarium Research Institute (MBARI) just discovered a new one. The new species of jellyfish has been named the Atolla reynoldsi, in honor  of the Monterey Bay Aquarium’s first volunteer.

“We named this stunning new species in honor of Jeff Reynolds in recognition of the 4.3 million hours of service that he and other volunteers have contributed to the Monterey Bay Aquarium over the past 38 years,” said MBARI Senior Education and Research Specialist George Matsumoto, who was the lead author on the description of this new species. “They have graciously given their time to educate the public about the wonders of the ocean. Aquarium volunteers have been instrumental in raising awareness about the fragility of the ocean and inspiring the public to care about the health of the ocean.”

The Atolla jelly is one of the most common residents of the ocean’s midnight zone, a region between so deep that no sunlight at all penetrates the water. With no light, there is no growth of plants or phytoplankton, so everything that lives there is either a predator or a scavenger. The Atolla jelly is an interesting looking creature. With a large scarlet bell, it has one tentacle that’s noticeably larger than the others.


But fifteen years ago, MBARI researchers spotted what looked to be a regular Atolla jelly, but with one difference: it was missing that long trailing tentacle. Since then, they’ve been studying it, which is no easy feat, considering where it lives.

Since that first sighting, MBARI researchers have been observing and collecting specimens of Atolla jellies that lack the trailing tentacle. Now, they’ve collected enough of them to make a definitive call.

A. reynoldsi is pretty big, compared to the other jellies in the Atolla genus. Still not huge — the largest they’ve found was only 5.1 inches in diameter — but it’s big enough to make it one of the largest of the Atollas.

“Like other deep-sea crown jellies, A. reynoldsi has a furrowed bell,” the researchers wrote. “A deep groove runs around the bell, separating the domed bell from the wide margin with thick segments, known as pedalia, containing finger-like lappets. The edge of the bell resembles a crown, earning this group of jellies its regal name. The ‘crown’ in A. reynoldsi has warty papillae and spiked ridges. Only one other species of Atolla—A. chuni, known from the South Atlantic and Southern oceans—has a similarly bumpy bell. A. reynoldsi also has a distinct gut that is shaped like a Greek cross.”

Aside from the lack of the trailing tentacle, A. reynoldsi also has a habit of coiling its tentacles. While the number of tentacles on an Atolla can’t be relied on to make an identification, the A. reynoldsi generally has anywhere from 26 to 39 tentacles.


Since they first spotted the rare jellyfish in April of 2006, MBARI researchers have only observed 10 specimens. As of this writing, they believe that it lives only in Monterey bay and lives at depths of 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,” explained Matsumoto. “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.”


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