Blue-spotted Shield Slug

Overview

The Blue-spotted Shield Slug (Chelidonura livida) is a distinctive marine gastropod belonging to the family Aglajidae. Often found in shallow, sandy environments, this carnivorous sea slug is recognized for its striking coloration and specialized sensory behaviors used to navigate its surroundings.

Appearance

This species typically features a smooth, black or dark brown body adorned with vibrant, electric blue spots or rings. The head is flared, and the tail ends in two uneven lobes, with the left side often longer than the right. Small sensory bristles located along the anterior edge of the head allow the slug to detect chemical cues in the mucus trails of its prey and potential mates.

Distribution & habitat

Chelidonura livida is widely distributed across the tropical western Indian Ocean, including the Red Sea, Madagascar, and the Arabian Sea, with records extending to Indonesia and northern Australia. It is primarily a sand-dwelling species, frequently observed on shallow intertidal sand flats, silty sea beds, and within seagrass meadows, often becoming more active at night.

Biology & behavior

As a predator, this slug feeds on small flatworms, using its sensory bristles to track them through the substrate. When threatened or handled, it can release a brownish-yellow secretion that is toxic to fish. During breeding periods, particularly in spring and early summer, these slugs are known to congregate and may form "mating chains" of multiple individuals. They reproduce by laying white, cocoon-like egg masses.