Common name : lucinids

Aspect : rounded, oval, or slightly compressed, slightly inequilateral; Some species (e.g., Codakia) are nearly circular, others (e.g., Lucinoma) are more elongate; smooth or with weak radial sculpture with prominent concentric ridges; brown, olive, or yellowish; reduced or simple hinge teeth

Feeding : lucinids have a unique dual feeding strategy - Chemosymbiosis (primary method)and although reduced, lucinids may also filter particles or absorb dissolved organic matter -; the clams host sulfur-oxidizing bacteria (symbionts) in their gill cells, symbionts oxidize hydrogen sulfide (H₂S) from the environment, producing energy to fix CO₂ providing themselves and their hosts with nutrition

Environment : cosmopolitan, but highest diversity in Indo-Pacific (especially Caribbean and Indo-West Pacific); most common in shallow tropical/subtropical waters (0–200 m) though some species live in abyssal (>6000 m) depths; in soft sediments (mud, sand, seagrass beds, mangroves, and organic-rich habitats); key requirement is sulfide-rich environments, because their symbiotic bacteria require sulfide