Atlantic Calico Scallop
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: gibbus · Pectinidae (Scallop family) · Bivalve (single valve); Fan-shaped
Species
Argopecten gibbus
Shell Type
Bivalve (single valve); Fan-shaped
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch (25mm) in diameter; typically ranges from 1 to 3 inches when fully grown.
Color & Pattern
Mottled pattern featuring vibrant orange-brown patches on a creamy white base with subtle pink undertones. Colors appear natural and well-preserved.
Rarity
Common; frequently found on the beaches of North Carolina after storms or high tides.
Habitat
Marine; found in shallow subtidal waters to depths of 400 feet, preferring sandy or shelly substrates.
Geographic Range
Western Atlantic from Delaware to Brazil, highly abundant in the Gulf of Mexico and off the Carolinas.
Description
An attractive, circular fan-shaped valve with approximately 17-23 radiating ribs. This specimen shows the characteristically 'puffy' or convex shape of the top valve with distinct 'ears' or auricles at the hinge.
Key Features
Highly convex (inflated) valves, equal-sized auricles (wings), and a distinctive calico-like color mottling that varies between every individual specimen.
Collector Value
Modest; mostly valued by hobbyists for their incredible variety of colors and patterns. Not a high-value rarity, but a staple for any Atlantic coast collection.
Condition Notes
Good; shows slight edge wear but retains excellent color intensity. Some minor erosion on the ribs, common for beach-found specimens. Grade: Good/Fine.
Interesting Facts
Unlike many bivalves, Calico Scallops can swim short distances by rapidly snapping their valves together to create jet propulsion. They have dozens of tiny, bright blue eyes along the edge of their mantle to detect light and movement.
Ecological Role
Active filter feeder that cleans the water column; a vital food source for sea stars, crabs, and various marine fish. Currently not a protected species.
Similar Species
Argopecten irradians (Bay Scallop) which is usually drabber (grey/brown) and flatter, and Caribachlamys sentis (Sentis Scallop) which has more irregular ribbing.
Beach Finding Tips
Best found at Holden Beach after a falling tide or following a winter storm. Look in the 'shell hash' lines where smaller, colorful shells accumulate.
Notes
Holden Beach, NC