The flat tree oyster has two thin, irregularly shaped valves joined by a long straight hinge.

The exterior is sculptured by a large number of rough, concentric rings with loose flakes and varies in colour from a pale brownish olive to a purplish black.

[2] The flat tree oyster is found in southern Florida, the Caribbean Sea and Gulf of Mexico, Colombia, Costa Rica, Cuba, Jamaica, Lesser Antilles, Puerto Rico, Venezuela, San Andrés and Brazil.

[4] The flat tree oyster is a filter feeder, drawing water into its shell and passing it through its gills, extracting plankton and small organic particles in the process.

When they have passed through several developmental stages they settle to the seabed, undergo metamorphosis and attach themselves with byssus threads as miniature adults.