Shell size to 24 mm; shell very compressed, almost flat. Sculpture of strong, low concentric ribs that form teeth-like projections on anterior and posterior dorsal margins. Umbones central. Color white. This species is not very common on Sanibel and Captiva. The shell in the main illustration was collected by Ken and Alice Piech at Blind Pass (bay side), Sanibel, on August 2018, at the peak of the 2018 Red Tide episode (photos by James F. Kelly.) The additional illustration shows a pair found by Leonard Geyer on Sanibel and donated to the Shell Museum in March 2014.