Calico Scallop (Atlantic Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell, fan/disc shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole shell, fan/disc shape
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches in width, which is average for this species. Adults typically range from 1.5 to 2.5 inches.
Color & Pattern
Soft creamy white to light peach base color with subtle, faint brownish-orange radial banding and mottling. Colors appear natural and slightly sun-softened. The interior is smooth and polished with white and peach tones.
Rarity
Common
Habitat
Shallow marine waters, typically found in sandy substrates, seagrass beds, and offshore shoals from the low intertidal zone down to depths of about 150 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina through Florida, the Gulf of Mexico, the Caribbean, and down to South America.
Description
A classic, symmetrical bivalve featuring a rounded, fan-like disc with well-defined radial ribs and smooth, equal auricles (ears) at the hinge. The exterior surface is finely ribbed with roughly 18 to 22 rounded radial plicae, giving it a classic scallop texture. The margins are tightly scalloped, matching the external ribbing.
Key Features
Equivalve, nearly equilateral fan shape with nearly equal-sized anterior and posterior ears at the hinge line, featuring 18-22 rounded radial ribs and a convex profile.
Collector Value
Moderately popular among shell collectors due to their pleasing symmetry and attractive color variations, though they are very common and typically inexpensive, often sold in souvenir shops and used in shell crafts for a few cents to a dollar per specimen.
Condition Notes
Good to Fine condition. The shell is intact with no major fractures or structural damage. Minor natural wear on the exterior surface but retaining good overall form and smooth margins. Collectibility grade is Fine.
Interesting Facts
Scallops are among the few bivalves that can actively swim by rapidly clapping their valves together to expel water, propelling themselves through the water column to escape predators like sea stars and fish. They also possess dozens of tiny, bright blue eyes along the edge of their mantle that can detect light and movement.
Ecological Role
Calico scallops serve as important filter feeders in marine ecosystems, helping to clear the water column of phytoplankton and suspended organic matter. They provide a vital food source for numerous marine predators including fish, rays, sea turtles, and crabs. Populations are generally robust and not currently endangered.
Similar Species
Bay Scallop (Argopecten irradians), which tends to have a flatter shell profile and slightly wider, fewer ribs (usually 17), and the Atlantic Deep-Sea Scallop (Placopecten magellanicus), which is much larger and flatter.
Beach Finding Tips
Best found by beachcombing along sandy Atlantic and Gulf coastlines, particularly after storm events or high tides. Look along the high tide wrack line where light, buoyant bivalves tend to accumulate in great numbers.