Wavy Bubble Snail

Overview

The Wavy Bubble Snail (Micromelo undatus) is a small, colorful marine gastropod belonging to the family Aplustridae. While historically considered a single circum-global species, recent research indicates that true M. undatus is restricted to the Atlantic and Caribbean basins, with similar populations in the Indo-Pacific now classified as separate species.

Distribution & habitat

This species is found in tropical and subtropical Atlantic waters, including the Caribbean, Florida, Bermuda, Brazil, and the eastern Atlantic islands such as the Canaries and Cape Verde. It typically inhabits shallow environments, ranging from the intertidal zone to depths of approximately 10 meters. They are most commonly observed on sandy or rocky substrates, with a preference for areas featuring algal turf.

Appearance

The Wavy Bubble Snail is characterized by a thin, lightweight, egg-shaped shell that features a distinct pattern of wavy brown axial lines crossed by two or three spiral lines. The animal itself is highly visible, possessing a translucent white or greyish body densely covered in opaque white spots. A vivid yellow-orange band typically edges the mantle and foot, often accompanied by a diffuse pale blue or green submarginal line.

Biology & behavior

Unlike many other gastropods, this snail lacks a protective operculum and rarely retracts into its shell, even when disturbed. It is active during both day and night. A notable biological defense mechanism involves its diet; the snail consumes cirratulid polychaete worms and incorporates their toxins into its own tissues to deter predators.