Atlantic Calico Scallop (Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled clam), whole matched pair (joined at the hinge), fan-shaped
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled clam), whole matched pair (joined at the hinge), fan-shaped
Family
Pectinidae (Scallop family)
Size
Approximately 2 inches in length and width, which is average for this species. Adults typically range from 1.5 to 2.5 inches.
Color & Pattern
Displays a mottled pattern of reddish-brown and purplish-pink speckles and blotches over a lighter whitish or cream base, typical of the calico color form. The interior of the exposed valve shows a glossy white surface with a dark purplish-brown coloration near the hinge area.
Rarity
Common
Habitat
Shallow marine waters, typically found in sandy or shelly substrates, often inhabiting offshore waters and grassy bays from the low intertidal zone down to depths of about 150 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through the Florida keys, the Gulf of Mexico, and into the Caribbean Sea.
Description
A charming and brightly patterned bivalve featuring nearly equilateral, rounded fan-shaped valves with distinct, prominent radial ribs. The exterior showcases fine textured growth lines crossing numerous well-defined ribs, while the symmetrical wings (auricles) flank a straight hinge line. The specimen is a matched pair, slightly opened to reveal the clean, porcelain-white interior.
Key Features
Nearly equivalve shell shape, prominent equal-sized auricles (ears) at the hinge, approximately 18 to 22 rounded radial ribs, and the characteristic calico mottling of reddish-brown spots on a light background.
Collector Value
Moderately popular among shell collectors and crafters due to their colorful patterns. Because they are common, individual specimens have a low monetary value (usually sold as inexpensive souvenirs or craft materials), but intact paired valves in fine condition are appreciated in beginner and intermediate collections.
Condition Notes
Good condition. The shell is a complete, intact matched pair with minimal wear on the exterior ribs and margins. Colors are natural and well-preserved with little to no sun-bleaching. Collectibility grade is Fine.
Interesting Facts
Unlike many bivalves that burrow or attach permanently, calico scallops are capable of swimming by rapidly clapping their valves together to expel water, allowing them to escape predators like starfish and crabs. They also possess dozens of tiny, bright blue eyes along the mantle edge that can detect light and movement.
Ecological Role
Calico scallops serve as an important food source for various marine predators, including fish, rays, sea turtles, and crabs. They are filter feeders, helping to clean the water column by consuming microscopic plankton and organic particles.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which tends to be slightly larger, has flatter ribs, and often inhabits shallower seagrass beds closer to shore.
Beach Finding Tips
Look for calico scallops washed up on ocean-facing beaches following storms or high tides. Unlike bay scallops that favor shallow grass flats, calico scallops live further offshore, so their empty shells frequently wash up on high-energy Atlantic and Gulf coast beaches.