Yellow Umbrella Slug

Overview

The Yellow Umbrella Slug (Tylodina perversa) is a distinctive marine gastropod known for its vibrant saffron-yellow coloration and a small, delicate, cap-like shell. It is frequently found in association with specific sponges, which provide both its primary food source and its characteristic pigment.

Appearance

This species typically reaches 3 to 7 cm in length. It features a thin, protein-based shell that is flattened and slightly offset to the left, often marked with irregular brown radial streaks or spots. The body is bright yellow to orange, matching the sponges it inhabits. Notable features include long, tubular, rolled rhinophores and two robust oral tentacles. A prominent, feather-like gill is visible on the right side of the body, tucked beneath the shell.

Distribution & Habitat

Tylodina perversa is found in the northeastern Atlantic, ranging from the British Isles down to the Canary Islands, as well as throughout the Mediterranean and Adriatic Seas. It primarily inhabits rocky, well-lit substrates at depths of 5 to 50 meters, where its preferred sponge hosts thrive.

Feeding

This slug is a specialized predator that feeds almost exclusively on sponges of the genus Aplysina, such as Aplysina aerophoba. It derives its vivid yellow color by sequestering pigments from these sponges. Research suggests it may also selectively store chemical compounds from its prey, which likely serve as a defense mechanism against predators.