Calico Scallop (Alternating Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell, fan shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole shell, fan shape
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch in height and width, which is on the smaller side for this species. Adults typically range from 1.5 to 2.5 inches.
Color & Pattern
Displays a mottled reddish-brown and white coloration with characteristic radial patterns typical of the species. Colors appear fresh and natural with sharp definition along the ribs.
Rarity
Common, frequently found washed ashore along southeastern US and Gulf of Mexico beaches.
Habitat
Shallow subtidal marine environments, typically found in sandy areas or seagrass beds in waters ranging from shallow depths to about 160 feet.
Geographic Range
Western Atlantic Ocean, from North Carolina through the Gulf of Mexico, the Caribbean, and down to South America.
Description
A charming, fan-shaped bivalve with prominent, rounded radial ribs extending from the umbo to the ventral margin. The margins are slightly scalloped, and the ears (auricles) near the hinge are relatively even.
Key Features
Symmetrical fan shape with roughly 18 to 22 rounded radial ribs, nearly equal-sized auricles at the hinge, and vibrant mottled color patterns.
Collector Value
Low to moderate commercial value, widely popular among beginner beachcombers and shell crafters. Typically sold in bulk or inexpensive souvenir shops.
Condition Notes
Good to Fine condition, largely intact with vibrant natural coloration and minimal wear on the margins. Collectibility grade is Fine.
Interesting Facts
Scallops are unique among bivalves for their ability to swim actively by rapidly clapping their valves together to expel water. They also possess dozens of simple blue eyes along the mantle edge.
Ecological Role
Serves as an important prey item for various marine carnivores including fish, sea stars, and octopuses. Filter feeders that help maintain water quality in marine ecosystems.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which tends to have a flatter profile and fewer, squarer ribs compared to the more convex Calico Scallop.
Beach Finding Tips
Best found by beachcombing along ocean-facing beaches in Florida and the Carolinas, particularly after storms or during low tide in high-tide shell drift lines.