Calico Scallop (Atlantic Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell, fan shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole shell, fan shape
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches in width and height, which is typical for an adult Calico Scallop. Adults generally range from 1 to 2.5 inches.
Color & Pattern
Cream to white base color adorned with characteristic reddish-brown to orange spots, flecks, and zigzag blotches arranged in radial patterns. Colors are entirely natural with vibrant markings along the prominent ribs and margins.
Rarity
Common to Very Common, frequently encountered by beachcombers along the southeastern coast of the United States and the Gulf of Mexico.
Habitat
Shallow subtidal marine environments, typically found on sandy bottoms, shell hash, and seagrass beds in water depths ranging from shallow low-tide lines down to 150 feet or more.
Geographic Range
Western Atlantic Ocean, from North Carolina southward through the Florida Keys, the Gulf of Mexico, and the Caribbean Sea down to Brazil.
Description
A classic, symmetrical bivalve shell featuring a rounded fan-like form with numerous distinct, prominent radial ribs (typically 18 to 22). The margins are crenulated to match the external ribs, and the auricles (ears) at the hinge are relatively even.
Key Features
Rounded, nearly equilateral fan shape with prominent radial ribs, characteristic brightly colored reddish-brown mottling or spots on a lighter background, and relatively equal-sized auricles at the hinge line.
Collector Value
Low to Moderate value as a commercial and craft shell, though highly prized by casual beachcombers. Pristine, brightly colored, paired butterfly specimens can command modest prices in shell shops.
Condition Notes
Good to Fine condition, displaying intact margins, minimal wear on the ribs, and bright natural coloration with no significant bleaching or boring organism damage.
Interesting Facts
Unlike many bivalves, Calico Scallops are free-swimming. They can propel themselves through the water by rapidly clapping their valves together to eject water, and they possess dozens of tiny, functional blue eyes along the mantle edge.
Ecological Role
Serves as an important prey species for a wide variety of marine predators including fish, rays, sea turtles, and carnivorous gastropods. They filter organic particles from the water column, contributing to water clarity.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which is typically slightly larger, has flatter ribs, and is less commonly found with the bright calico-style mottling.
Beach Finding Tips
Look along high-tide wrack lines on sandy ocean-facing beaches, especially after storms or strong onshore winds in Florida and the Carolinas.