Calico Scallop (also known as the Atlantic Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled mollusk), fan or disc-shaped whole shell
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled mollusk), fan or disc-shaped whole shell
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 inches in diameter, which is typical for an adult Calico Scallop. Fully grown specimens generally range from 1.5 to 2.5 inches.
Color & Pattern
This particular specimen exhibits pale, sun-bleached cream and yellowish tones. Natural calico scallops typically feature mottled patterns of reddish-brown, orange, purple, or yellow on a white background, but this shell is heavily weathered and washed out to off-white and pale yellow.
Rarity
Very Common. This is one of the most frequently encountered shells by beachcombers along the southeastern United States and Gulf coasts.
Habitat
Shallow marine waters, primarily inhabiting sandy bottoms, seagrass beds, and offshore shoals ranging from the intertidal zone down to about 160 feet (50 meters).
Geographic Range
Western Atlantic Ocean, extending from North Carolina down through Florida, the Gulf of Mexico, Bermuda, and the Caribbean Sea.
Description
A classic fan-shaped bivalve shell featuring prominent, radiating ribs and distinct growth lines. The surface shows a slightly worn texture from wave action, with rounded margins and a classic auricle (wing) structure at the hinge line.
Key Features
Nearly equilateral, rounded fan shape with 18 to 22 radiating ribs, and unequal ears (auricles) at the hinge where one side is slightly larger than the other.
Collector Value
Low commercial or collector value due to commonness and weathered condition. They are frequently gathered in large quantities for craft projects and tourist souvenirs rather than elite collections.
Condition Notes
Fair condition. The shell is intact but heavily sun-bleached with a worn exterior, lacking its vibrant natural mottled coloration. Collectibility grade is Fair.
Interesting Facts
Unlike many bivalves that burrow or stay attached, calico scallops can swim short distances by rapidly clapping their valves together to expel water, using a row of tiny blue eyes along their mantle edge to detect motion.
Ecological Role
Calico scallops serve as an important food source for various marine predators including fish, rays, sea stars, and octopuses. They filter phytoplankton from the water column, helping to maintain water clarity.
Similar Species
Bay Scallop (Argopecten irradians), which tends to have slightly flatter shells, fewer ribs (usually 17), and a more northern distribution.
Beach Finding Tips
Look along high-tide lines on sandy ocean-facing beaches, especially after storms or strong offshore winds. Shell piles and wrack lines are prime locations.