Three-lobed T-bar Nudibranch

Overview

The Three-lobed T-bar Nudibranch is a striking, colorful sea slug widely distributed across the tropical Indo-Pacific, including the Red Sea. Known for its rigid, elongated body and distinct mantle shape, this species is a common sight for divers exploring tropical reefs and sandy habitats.

Appearance

This nudibranch is easily identified by three prominent, rounded triangular lobes on its mantle: one on each side of the body and a third that arches posteriorly over the gills. Its body coloration is highly variable, ranging from orange and red to brown, often featuring mottled patterns or yellow and orange spots. A characteristic thin, often continuous purple line typically rims the edge of the mantle and foot. The gills and rhinophores are retractile, and the animal possesses a long, recurved dorsal "horn" behind the gills.

Biology & behavior

Active during the day, this species uses its dorsal horn as a defensive lure. This structure attracts potential predators to a part of the body that contains concentrated, distasteful chemicals derived from its diet, effectively deterring attacks. The nudibranch's rigid body and bright colors serve as further warnings to would-be threats. It is frequently found in shallow tropical waters, often inhabiting sandy or rubble-strewn areas where it can be seen moving across the substrate.

Feeding

This nudibranch is a specialized feeder, primarily consuming sponges belonging to the genus Dysidea. It stores chemical compounds from these sponges within its own mantle glands to fuel its defensive mechanisms.