Atlantic Calico Scallop (also known simply as Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled clam), whole shell, fan shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled clam), whole shell, fan shape
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches in width, which is average for this species. Adults typically range from 1.5 to 2.5 inches.
Color & Pattern
Pale greyish-white base color with subtle, mottled darker greyish or brownish markings typical of a sun-bleached or weathered specimen. The natural colors of live specimens include a mottled mix of white, red, brown, yellow, and purple patterns.
Rarity
Very Common, frequently washed up on beaches throughout its native range.
Habitat
Found in shallow marine waters, typically in sandy or shelly substrates, often associated with seagrass beds from the low intertidal zone down to depths of about 150 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through Florida, the Gulf of Mexico, and the Caribbean Sea.
Description
An attractive, roughly symmetrical fan-shaped bivalve with distinctive radial ribs and prominent, ear-like projections (auricles) flanking the umbo at the hinge. The exterior features strong, rounded radiating ribs that give the margin a scalloped edge.
Key Features
Nearly equilateral fan shape, prominent radial ribs (usually around 18-22), unequal auricles at the hinge line characteristic of scallops, and slightly inflated valves.
Collector Value
Low to moderate commercial and collectible value due to their abundance, though pristine, brightly colored multi-hued specimens are popular in shell crafts and beginner collections.
Condition Notes
Weathered and sun-bleached with a uniform greyish tone, showing some minor wear along the margins, but structurally intact as a single valve. Collectibility grade: Good.
Interesting Facts
Scallops are unique among bivalves because they are capable of active swimming. By rapidly clapping their valves together, they expel water to jet-propel themselves away from predators like starfish.
Ecological Role
Serves as an important prey item for various marine predators including fish, rays, sea turtles, and sea stars. They filter feed on phytoplankton, helping to maintain water clarity in coastal ecosystems.
Similar Species
Rough Scallop (Argopecten irradians concentricus), which generally has fewer, wider ribs and prefers shallower estuarine seagrass beds.
Beach Finding Tips
Look along high tide wrack lines on sandy beaches in the southeastern United States and Gulf Coast, especially after storm events or rough seas.