Atlantic Calico Scallop (also known as Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten 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 0.75 to 1 inch (around 2 cm), which is typical for a juvenile or smaller adult specimen. Adults of this species normally range from 1 to 2.5 inches.
Color & Pattern
Mottled reddish-brown and orange patterns resembling calico fabric against a whitish or cream background, creating a vibrant speckled appearance. Colors are natural and bright. The interior shows matching brownish hues near the hinge with a clean white margin.
Rarity
Very Common
Habitat
Shallow marine waters, typically found in sandy or shelly substrates, often associated with seagrass beds or moderately energetic offshore waters ranging from the intertidal zone down to depths of about 150 feet.
Geographic Range
Western Atlantic Ocean, from North Carolina southward through the Florida Keys, the Gulf of Mexico, and the Caribbean down to South America.
Description
A charming and compact bivalve featuring a classic fan shape with strongly developed, rounded radial ribs radiating from the umbo (beak). The margins are finely scalloped, and the auricles (ears) at the hinge line are slightly unequal in size. Its mottled calico coloration provides excellent natural camouflage.
Key Features
Nearly equilateral fan shape, prominent convex radial ribs (typically around 18 to 22), unequal auricles at the hinge, and characteristic mottled reddish-brown calico spotting.
Collector Value
Low to moderate commercial value due to high abundance, but heavily collected by beachcombers and used extensively in shell craft and jewelry making. Typically sold in bulk or as low-cost individual specimens.
Condition Notes
Intact single valve in very good condition with vivid natural coloration, minimal wear along the margins, and no visible predator bore holes. Collectibility grade: Fine.
Interesting Facts
Unlike most bivalves that burrow or attach permanently, calico scallops are capable of swimming short distances by rapidly clapping their valves together to expel water, using a row of tiny, bright blue eyes along their mantle edge to detect light and shadow.
Ecological Role
Serves as an important prey item for various marine predators including fish, rays, sea turtles, and octopuses. They act as suspension feeders, filtering phytoplankton from the water column and helping to maintain water clarity.
Similar Species
Bay Scallop (Argopecten irradians), which tends to have slightly flatter shells with fewer ribs (usually 17 or fewer) and a more northern distribution.
Beach Finding Tips
Look along sandy Atlantic and Gulf Coast beaches, especially after storms or high tides. Sift through shell drift lines where light, fan-shaped bivalves tend to wash ashore intact.