Atlantic calico scallop

Argopectin gibbus

Family Pectinidae - scallops

Bivalve (2 shells); shell circular, fan-like, slightly inflated, with extensions or wings on either side of beaks, wings equal in length; color white with reddish purple blotching, usually with lighter colored rib in the center, right shell with less coloration (mostly white) than left shell, many variations of color and patterns; 17-23 (usually 20) strong radiating ribs, grooves between ribs on left shell with tiny concentric threads; beak central, pointed; insides with reddish brown on upper portion, strong radiating grooves; left shell slightly more convex or inflated than right shell.
Similar Species
The circular shape with equal length wings, and the light background with various mottling usually distinguishes this scallop. The bay scallop is usually a solid color with white interior and the right shell (which is usually white) is distinctly more convex than the left shell. Also, the bay scallop has 12-17 ribs while the calico scallop has 17-23 (excluding the wings).
Gulf and high salinity bays, free-living, does not burrow
Maximum Size
6 cm (2 1/3 in)
Other Common Names
Previous Scientific Names
Rarely found north of Port Aransas.