Buttercup Lucine

The buttercup lucine grows to a length of up to 6 centimetres (2.4 in). It has a pair of equal sized, nearly circular, inflated valves joined at a many-toothed hinge. The exterior is smooth and white and is etched with fine concentric lines running parallel with the margin which show the animal's annual growth stages. The interior of the valves is buttercup yellow. When examining an empty valve, the pallial line (formed by the attachment of the mantle muscles) can be seen running parallel with the margin with the two muscle scars nearer the hinge. These show where the strong adductor muscles that held the valves together were attached. The anterior scar (nearer the animal's head) is parallel with the pallial line, a fact that distinguishes this species from the otherwise similar chalky buttercup (Anodontia philippiana).

The buttercup lucine is found in shallow waters in the western Atlantic and the Caribbean Sea. Its range extends from Bermuda and North Carolina southwards to the Gulf of Mexico and Costa Rica, and eastwards to Barbados. It burrows in soft sediment to depths of 22 cm (9 in) and is found in lagoons, inlets and bays just below low water mark. It tolerates high salinities and seems to prefer fine-grained or muddy sand.