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The mysterious Bathydevius caudactylus was observed by MBARI’s remotely operated vehicle Tiburon in the outer Monterey Canyon off the coast of California, at a depth of approximately 1,900 meters.
2002 MBARI
2002 MBARI
In early 2000, the scientists at Monterey Bay Aquarium Research Institute (MBARI) were sitting in the control room for their deep-diving remotely operated vehicle when they saw a bizarre creature swimming in the midnight zone of the ocean. “We were looking around at each other, sort of scratching our heads,” said Bruce Robison, one of the researchers on the team. This was the first time the MBARI research team caught a glimpse of the creature they later nicknamed the “mystery mollusc.” “[It] didn’t look like anything else we’d ever seen,” Bruce said. “It’s a pretty funny looking animal. … It sort of looks like it was made up from spare parts left over from making a bunch of other animals.”
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The creature is transparent and bioluminescent, with a cavernous hood on one end and a flat tail with finger-like projections on the other. It also has a protruding foot, much like a snail’s. After more than twenty years, Bruce Robison and his team have encountered 157 individuals of this strange species, and have now published a detailed description of the mollusk in the journal Deep-Sea Research Part I. Through observation and DNA sequencing analysis, they have identified that this mystery creature is a type of nudibranch, also known as a sea slug. They’ve named it Bathydevius caudactylus. This nudibranch also stands out as the first known nudibranch species to live in the deep water column. Nudibranchs are commonly found in shallower waters, and only a few species are known to live on the seafloor. To Robison, this exciting discovery only shows how much we don’t know about the deep sea and how important deep-sea research is. “The deep sea ecosystem is the largest one on the planet,” he said. “But we only ever see the top of it. At least most of us … if we ever hope to live in harmony with our planet, we’d better understand all that’s out there and how it all works. Otherwise, we’re liable to screw it up.”
Have another scientific discovery you want us to cover on a future episode? Email us at [email protected] — we might feature your idea on a future episode! Listen to Short Wave on Spotify and Apple Podcasts. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. This episode was produced by Jessica Yung and Gus Contreras. It was edited by Rebecca Ramirez and Christopher Intagliata. It was fact-checked by Tyler Jones. The audio engineers were David Greenberg and Patrick Murray.