Atlantic Calico Scallop (also known simply as Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole individual valve with fan shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole individual valve with fan shape
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 inches in width, which is a very typical size for an adult specimen. Adults generally range from 1 to 2.5 inches.
Color & Pattern
Striking and vibrant pattern of mottled reddish-brown and dark chocolate streaks or rectangular blotches radiating from the umbo (beak) down to the ventral margin, interspersed with lighter cream and yellowish background highlights. The coloration is completely natural and well-preserved.
Rarity
Very Common, frequently washed up on beaches throughout its native range, especially after storms or high tides.
Habitat
Shallow marine waters, typically found resting on sandy or shelly substrates in bays, sounds, and offshore marine environments from the intertidal zone down to depths of about 160 feet (50 meters).
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through Florida, the Gulf of Mexico, the Caribbean, and south to parts of South America.
Description
A classic, attractive bivalve shell featuring a symmetrical fan shape with prominent, rounded radial ribs extending from the hinge. The exterior surface is textured with fine growth lines crossing the sturdy ribs. The hinge area displays well-formed, equal-sized auricles (ears) flanking the central umbo.
Key Features
Rounded fan-shaped valve, approximately 18 to 22 prominent radial ribs, nearly equal-sized auricles at the hinge line, and a distinctive mottled or banded pattern of reddish-brown and white.
Collector Value
Low to moderate commercial or monetary value due to their abundance, but highly prized by beachcombers for their brilliant colors and patterns. They are frequently used in shell crafts and sold in souvenir shops.
Condition Notes
Good to Fine grade condition. The shell is structurally intact as a single valve with vivid natural coloration and minimal wear. A slight chip is visible on the left margin, but overall the specimen retains high aesthetic and structural integrity.
Interesting Facts
Unlike many bivalves that burrow or stay permanently attached, Calico Scallops are capable of active swimming. By rapidly snapping their valves together, they expel jets of water to propel themselves away from predators like starfish.
Ecological Role
Calico scallops serve as an important prey item for various marine carnivores, including sea stars, crabs, fish, and octopuses. They are filter feeders that help maintain water clarity by consuming suspended phytoplankton.
Similar Species
Rough Scallop (Argopecten nucleus) and Pacific Bay Scallop (Argopecten irradians). The Atlantic Calico Scallop can be distinguished by its slightly more inflated shell and specific rib count and geographic location.
Beach Finding Tips
Look along high-tide wrack lines on sandy ocean beaches or gulf-facing shores, particularly in Florida and the Carolinas, shortly after a strong offshore wind or winter storm.