Common name : tree oysters, hammer oysters or purse oysters

Aspect : inequivalve, irregular, often fan-shaped or sub-rectangular; left valve usually more convex and cemented; cemented by byssal threads; hinge straight or slightly curved with small teeth in some species; external ligament running along most of the hinge line (a key diagnostic trait); size up to 15 cm

Feeding : filtration of microorganisms in suspension (phytoplankton, zooplankton, detritus, and organic particles)

Environment : Indo-Pacific, Caribbean, West Africa, Eastern Pacific; in intertidal to shallow subtidal (0–20 m); attached to mangrove roots, rocks, coral rubble, piers, or seagrass