Atlantic Calico Scallop (also known as Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled, whole shell), fan-shaped
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled, whole shell), fan-shaped
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
Base color is a creamy off-white or light yellowish-tan, adorned with subtle darker mottling and distinct, bright reddish-brown or burgundy spots concentrated along the ribs and toward the ventral margin. The colors appear natural with some slight sun-bleaching.
Rarity
Common, frequently found washed ashore on beaches within its geographic range.
Habitat
Found in shallow marine waters, typically in sandy substrates, seagrass beds, or shell gravel from the intertidal zone down to depths of about 160 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina through the Gulf of Mexico, Florida, and the Caribbean down to South America.
Description
An attractive, roughly symmetrical fan-shaped bivalve shell featuring approximately 18 to 21 prominent, rounded radial ribs. The hinge area has distinct, unequal auricles (ears) characteristic of scallops, giving it a classic winged appearance. The texture is slightly ridged and chalky with fine growth lines crossing the ribs.
Key Features
Rounded, prominent radial ribs (usually 18-21), unequal 'ears' at the hinge line characteristic of the Argopecten genus, and a convex valve profile.
Collector Value
Low to moderate commercial value, highly popular among casual beachcombers and beginner shell collectors due to their attractive patterns and abundance.
Condition Notes
Good condition, single valve intact with some minor encrusting calcareous tube worm remnants on the surface. Minimal chipping along the margin. Collectibility grade: Good to Fine.
Interesting Facts
Unlike many bivalves that burrow or cement themselves, Calico Scallops are capable of swimming by rapidly clapping their valves together to expel water, allowing them to escape predators.
Ecological Role
Serves as an important prey species for fish, rays, sea turtles, and carnivorous gastropods. They are filter feeders that help clear particulate matter from the water column.
Similar Species
Bay Scallop (Argopecten irradians), which is typically slightly larger, has flatter ribs, and prefers very shallow estuarine grass beds.
Beach Finding Tips
Look along high-tide wrack lines after storms or strong onshore winds, particularly on Gulf-facing Florida beaches and barrier islands.