Deep-sea dorid nudibranch

Deep-sea dorid nudibranch (Bathydoris aioca)

Bathydoris aioca, an unusually large (~30 cm) deep-sea nudibranch, was part of a unique community of invertebrates gathered around the anchor of the Slope Base profiler mooring in 2900 meters (~9500 feet) of water, also including flytrap anemones, galatheid crabs, and sea cucumbers.
Photo credit: NSF-OOI/UW/CSSF, Dive R2258, V22

A large, deep-sea nudibranch, or sea slug, this gastropod is found on soft sediments in the deep NE Pacific. One was seen near the anchor of the Slope Base Shallow Profiler mooring, and was 30 cm (nearly a foot) long. They have a bumpy exterior, long, thin feeding tentacles, tiny ear-like rhinophores (which act as chemosensors), and posterior external gills.