Each valve is a pale brown colour with whitish rays radiating from the umbo, the raised hump that is the first part of the shell to form when the animal is a juvenile.

[2] Lister's tree oyster occurs in southern Florida, the Caribbean Sea and Gulf of Mexico, Bermuda, the West Indies, the Cayman Islands and Brazil.

[4] In Little Cayman it occupies a particular zone on the lower shore and shallow subtidal region of sheltered bays where it is common under large stones, often accompanied by the rock boring urchin (Echinometra lucunter).

In more exposed locations on the island it is replaced by the closely related flat tree oyster (Isognomon alatus).

[5] Lister's tree oyster is a constituent of the characteristic invertebrate fauna of the mangrove swamps fringing the southern part of Florida.