Calico Scallop (Atlantic Calico Scallop)
Kingdom: Animalia, Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (single valve shown); fan-shaped shell with radiating ribs and lateral ears.
Species
Argopecten gibbus
Shell Type
Bivalve (single valve shown); fan-shaped shell with radiating ribs and lateral ears.
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches (38-50mm) in diameter. This specimen is mid-sized for the species, which typically averages 1 to 3 inches.
Color & Pattern
Mottled base of cream and white with vibrant patches of orange, reddish-brown, and occasional purple-pink flecks. The pattern is 'calico'—scattered, irregular spots and bands that are more intense on the left (upper) valve. One ear shows a reddish-pink hue.
Rarity
Very Common. These are signature shells for beachcombers along the Southeastern United States and Florida coastlines.
Habitat
Found in marine environments, preferring open sandy or gravelly bottoms at depths ranging from 10 to 400 feet. They are most common in offshore waters.
Geographic Range
Western Atlantic, from North Carolina southward to the Gulf of Mexico, the Caribbean, and Brazil.
Description
A classic fan-shaped bivalve with roughly 19 to 22 radiating ribs. The ribs are rounded and robust. This valve is moderately convex. It features two 'ears' (auricles) at the hinge; on the Calico Scallop, these ears are usually unequal in size. The interior is generally white with some exterior coloring bleeding through near the margins.
Key Features
Rounded ribs (unlike the flat-topped ribs of the Bay Scallop); motley 'calico' color pattern; roughly equal-length ears; more convex shape than the similar Argopecten irradians.
Collector Value
Low monetary value ($1-$5) due to high abundance, but high aesthetic desirability for casual collectors. Large specimens with exceptional purple or bright orange coloration are more prized.
Condition Notes
Good / Fair collection grade. The shell is intact with good color preservation, though the edges show slight wear/chipping from wave action. There is minor calcium buildup or weathering in the grooves between the ribs.
Interesting Facts
Unlike many clams, Calico Scallops can swim by rapidly clapping their shells together to expel water (jet propulsion). They also possess dozens of tiny, bright blue 'eyes' located along the edge of their mantle that detect movement and light changes.
Ecological Role
Active filter feeders that help clarify seawater. They are a vital food source for sea stars, crabs, octopuses, and humans. Historically, they supported a major commercial fishery in the Southeastern US.
Similar Species
Bay Scallop (Argopecten irradians) which has flatter ribs and is usually drabber/grey; Rough Scallop (Aequipecten muscosus) which has small scales or spines on the ribs.
Beach Finding Tips
Best found after storms or strong onshore winds on Florida and Carolina beaches. Look in the 'wash' area at low tide where shell fragments accumulate.