Atlantic Calico Scallop (also known as Calico Scallop)
Phylum Mollusca, Class Bivalvia, Order Pectinida, Family Pectinidae, Genus Argopecten, Species Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole individual valve, fan-shaped
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole individual valve, fan-shaped
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch in width, which is slightly smaller than average for this species. Adults typically range from 1 to 2.5 inches.
Color & Pattern
Vibrant mottling of reddish-orange, brown, and cream patches radiating from the umbo, typical of the calico color form. Colors are natural and glossy, displaying standard exterior pigmentation for the species.
Rarity
Common, frequently washed up on beaches throughout its native range, particularly after storms.
Habitat
Shallow marine waters, typically found in sandy bottoms, seagrass beds, and offshore shoals from the low tide line down to depths of 150 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through Florida, the Gulf of Mexico, and the Caribbean Sea.
Description
A charming and brightly patterned bivalve featuring approximately 18 to 22 well-rounded, strong radial ribs. The shell has an inequilateral, slightly slanted fan shape with asymmetrical auricles (ears) at the hinge line. The margins are scalloped to interlock tightly when closed.
Key Features
Unequal auricles (ears) at the hinge line, rounded radial ribs numbering around 20, and the characteristic mottled reddish-brown calico color pattern.
Collector Value
Low to moderate commercial value. While widely sold in souvenir shops and popular with beginner beachcombers, exceptional or perfectly matched pairs can be desirable for crafts and decorative displays.
Condition Notes
Good to Fine condition. The single valve is intact with sharp margins, retains its original glossy coloration, and shows no significant structural damage or boring holes.
Interesting Facts
Unlike many bivalves, calico scallops are capable of swimming short distances by rapidly clapping their valves together to expel water, allowing them to escape predators like starfish.
Ecological Role
Calico scallops are filter feeders that help maintain water clarity. They serve as an important food source for various fish, crabs, and sea turtles, and support commercial fisheries in certain regions.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which tends to have more flattened ribs and a more symmetrical shape, and the Rough Scallop (Aequipecten muscosus), which features rougher, scaly ribs.
Beach Finding Tips
Look along high-tide wrack lines on sandy ocean beaches, especially early in the morning following strong onshore winds or winter storms.