Common name : ark clams or ark shells

Aspect : equivalve (both valves equal) but inequilateral (hinge not centered); elongate-oval, rectangular, or trapezoidal often inflated (convex valves); radial ribs (usually 20–40) smooth, nodular or hairy; numerous small, similar teeth in a straight or slightly curved row along the hinge plate; size varies widely from 1 cm (Tegularca) to over 15 cm (Anadara granosa)

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

Environment : common in tropical and subtropical waters, most diverse in Indo-Pacific; from shallow subtidal to intertidal (200 m); buried or bycaught in sand, mud, gravel, or attached by byssus to hard substrates