Atlantic Calico Scallop (also known as the Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell valve, fan-shaped disc
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole shell valve, fan-shaped disc
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch in length and width, which is average for this species. Adults typically range from 1 to 2 inches.
Color & Pattern
Displays a mottled pattern of purplish-brown, reddish-brown, and white splashes resembling calico fabric. The coloration is natural and vivid, featuring distinct radial ribs.
Rarity
Common, frequently found washed ashore on beaches within its geographic range, especially after storms.
Habitat
Shallow marine waters, typically found on sandy bottoms, seagrass beds, and offshore shoals from the intertidal zone down to about 150 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina through the Gulf of Mexico, Caribbean Sea, and down to South America.
Description
A charming, fan-shaped bivalve with roughly 18 to 21 rounded, prominent radial ribs. The hinge features distinct small auricles (ears), and the margins are scalloped to match the external ribs, creating a delicate yet sturdy structure.
Key Features
Rounded fan shape with 18-21 prominent radial ribs, nearly equilateral valves with somewhat unequal ears at the hinge, and a distinctive multicolored calico mottling.
Collector Value
Low to moderate commercial and collectible value. While extremely common, they are popular among casual beachcombers and crafters due to their vibrant patterns.
Condition Notes
The specimen is an intact single valve in good condition with well-preserved natural coloration and minimal wear along the margins. Collectibility grade is Good to Fine.
Interesting Facts
Unlike many bivalves, calico scallops are capable of swimming short distances by rapidly clapping their valves together to expel water, allowing them to escape predators like starfish.
Ecological Role
Calico scallops serve as an important food source for various marine predators including fish, rays, and sea turtles. They are filter feeders that help maintain water quality in marine ecosystems.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which is generally slightly larger with flatter ribs, and the Rough Scallop (Aequipecten muscosus), which has scaly ribs.
Beach Finding Tips
Look along shell-heavy drift lines on sandy Atlantic and Gulf beaches, particularly following rough weather or high tide. Early morning right after the tide recedes yields the best finds.