Variable Worm Snail

Thylacodes variabilis

Thylacodes variabilis is a worm snail characterized by its white-brown shell, which can be coiled or partly straight and reach a diameter of up to 14 millimeters. The shell often has a coating of coralline algae or sand grains, and it is notable for lacking an operculum, setting it apart from other snails. The body color of this species is polychromatic, with individuals displaying a range of colors from white to beige, brown, yellow, and orange. This variability in coloration can help divers identify them during encounters. This species is commonly found in the rocky intertidal zones of Hawaiʻi and the tropical Pacific, residing in open environments such as tide pools, shallow reef flats, and rocky reefs. Thylacodes variabilis typically inhabits depths of up to 1 meter, attaching its shell to both natural and artificial surfaces. They are also known to be transported on vessel hulls and drifting substrates, which can aid in their dispersal. Thylacodes variabilis feeds by filtering algae and detritus from the water column, utilizing its specialized feeding mechanism. The reproductive strategy involves females brooding their offspring in egg capsules that are attached to the interior of their shells. This species has a widespread presence in suitable habitats. The conservation status of Thylacodes variabilis is not evaluated, but it is considered common in its range.