Family Basterotiidae

Shell size to 14 Shell squarish, or with relatively angled "corners." Shell with delicate granular sculpture in well-preserved specimens. The main feature of this small white bivalve is the well-developed cardinal tooth present on the hinges of both valves. A ridge is present near the posterior margin. Loose valves found by Susan J. Hewitt on Turner Beach (Captiva), in December 2015, December 2016, and December 2021.

Shell to 10 mm in length. Shape rhomboid-quadrangular, inflated, white, with very fine, commarginal growth lines. The two (loose) valves illustrated were collected on December 2021 by Susan Hewitt at Turner Beach on Captiva Island.