Calico Scallop (Alternative names: Peale's Scallop, Magpie Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled clam), whole shell, fan or disc-shaped
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled clam), whole shell, fan or disc-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
Off-white to cream base color heavily mottled with distinct reddish-brown, purple, or orange blotches and squares arranged in radial patterns resembling calico fabric. The coloration is completely natural and well-preserved.
Rarity
Common (frequently found washed ashore on beaches within its geographic range, especially after storms).
Habitat
Found in marine environments, typically inhabiting shallow subtidal waters down to about 150 feet, preferring sandy substrates and seagrass beds.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina south through Florida, the Gulf of Mexico, the Caribbean, and down to South America.
Description
An attractive, solid bivalve shell featuring a rounded fan-like shape with approximately 18 to 21 strong, rounded radial ribs. The exterior exhibits a vibrant calico pattern of reddish-brown spots over a pale background. The margins are crenulated to match the external ribs, forming a tightly interlocking edge when both valves are closed.
Key Features
Nearly equilateral and equivalve fan shape, distinct radial ribs numbering around 18-21, characteristic mottled reddish-brown calico spotting, and small, unequal auricles (ears) at the hinge.
Collector Value
Low to moderate commercial value. While very popular among casual beachcombers and crafters, commercial abundance keeps individual specimen prices low (typically under a few dollars), though high-color variants are prized.
Condition Notes
Good to Fine grade. The shell is intact with minimal wear on the umbo, retaining its original bright coloration and crisp sculptural ribs with no major chips or structural damage.
Interesting Facts
Unlike many bivalves that burrow or attach permanently, Calico Scallops are capable of swimming short distances by rapidly clapping their valves together to expel water, allowing them to escape predators.
Ecological Role
Serves as an important prey item for various marine carnivores including sea stars, octopuses, rays, and carnivorous gastropods. They are filter feeders that help maintain water clarity in coastal ecosystems.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which tends to be slightly larger with flatter ribs and less vibrant calico spotting, and the Rough Scallop (Aequipecten muscosus), which has scaly ribs.
Beach Finding Tips
Look along Gulf and Atlantic beaches of Florida, particularly following heavy winds or tropical storms. Sift through shell piles near the high tide line where lightweight bivalves tend to accumulate.