MBARI researchers discover remarkable new swimming sea slug in the deep sea

MBARI researchers have discovered a remarkable new species of sea slug that lives in the deep sea. Bathydevius caudactylus swims through the ocean’s midnight zone and lights up with brilliant bioluminescence. With a voluminous hooded structure at one end, a flat tail fringed with numerous finger-like projections at the other, and colorful internal organs in between, the team initially struggled to place this animal in a group. Because the animal also had a foot like a snail, they nicknamed this the “mystery mollusc."

The team first observed the mystery mollusc in February 2000 during a dive with the institute’s remotely operated vehicle (ROV) Tiburon offshore of Monterey Bay at 2,614 meters (8,576 feet) deep. They leveraged MBARI’s advanced and innovative underwater technology to gather extensive natural history information about the mystery mollusc. After reviewing more than 150 sightings from MBARI’s ROVs over the past 20 years, they published a detailed description of this animal.

Bathydevius caudactylus is just one of many fascinating discoveries MBARI has made in the midnight zone. To date, MBARI technology has been used to document more than 250 deep-sea species previously unknown to science.

Learn more: https://www.mbari.org/news/mbari-rese...

Research Publication:
Robison, B.H. and S.H.D. Haddock. 2024. Discovery and description of a remarkable bathypelagic nudibranch, Bathydevius caudactylus, gen. et. sp. nov. Deep-Sea Research Part I, https://doi.org/10.1016/j.dsr.2024.10...

Video credits:
Producer/editor: Kyra Schlining
Script: Raúl Nava, Bruce Robison, Kyra Schlining
Science advisors: Steve Haddock, Bruce Robison
Narrator: Bruce Robison
Production team: Raúl Nava, Kyra Schlining, Nancy Jacobsen Stout, Susan von Thun
Music: Gently Onwards (YouTube audio library); azure ambient (https://www.pond5.com/); life time ambient inspiring (https://www.pond5.com/)
Stock media of shallow nudibranchs provided by https://www.pond5.com/
01:41 Fishtales; 01:44 AlexanderSutormin; 02:15 JohnvanLent; 02:19 RobJacobs