The Chalky Lucine, Pegophysema schrammi (Crosse, 1876) is the largest of the local species of the diverse bivalve family Lucinidae. It commonly reaches 80 mm (about 3.1 inches) in length. Its shell is very inflated ("fat") and similar to the also local Buttercup Lucine (Anodontia alba), but it lacks the smooth, bright-yellow inner shell surface of this species. Instead, the inside surface of the Chalky Lucine’s valves is whitish and very rough, almost pebbly. Lucinids such as the Chalky Lucine are mostly filter-feeders that also host symbiotic bacteria in their gills, which provide them with an additional source of food.
The Chalky Lucine, Pegophysema schrammi, from Sanibel. Photos by José H. Leal.