New Bioluminescent Sea Slug Discovered in Deep Ocean

Researchers from MBARI have identified Bathydevius caudactylus, the first nudibranch to inhabit the ocean's midnight zone, after two decades of study.

Bathydevius caudactylus, nicknamed the 'mystery mollusc,' was first observed in 2000 and has been documented over 150 times by MBARI researchers.
This sea slug is unique for living in the deep water column, between 3,300 and 13,100 feet, unlike most nudibranchs that dwell on the seafloor or in coastal areas.
The species uses a gelatinous hood to trap crustaceans, employing a feeding strategy similar to a Venus fly trap, and can emit bioluminescence to deter predators.
The discovery involved extensive use of advanced underwater technology, allowing scientists to study the slug's luminous behavior in its natural habitat.
Genetic analysis has led to the creation of a new family, Bathydeviidae, highlighting the slug's distinct evolutionary path among nudibranchs.