This marine slug was first nicknamed “mystery mollusk”

In 2000, an exploration off the coast of Monterey encountered an animal that was difficult to classify. A wide hood, a tail lined with projections and colorful organs give an unusual silhouette. A muscular foot makes one think of a mollusk, without sufficient to solve the riddle.

Researchers provisionally call it the “mystery mollusk.” More than one hundred and fifty observations and anatomical and genetic studies then make it possible to recognize Bathydevius caudactylus, a nudibranch living in the deep water column, unlike many bottom marine slugs.

Its hood captures crustaceans, but scientists still don’t fully understand how this slow swimmer catches fast prey. An observation also shows a bright projection of its tail detaching, likely to distract a predator. The scientific name has replaced the nickname, but some of its behavior remains mysterious.