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). This specimen appears to be a worn individual valve fragment, roughly fan-shaped.
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled). This specimen appears to be a worn individual valve fragment, roughly fan-shaped.
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch in length and width, which is slightly smaller than average. Adults typically range from 1.5 to 2.5 inches.
Color & Pattern
The exterior displays a mottled, weather-worn pattern of faint reddish-brown streaks and dashes over an off-white or beige base, characteristic of a sun-bleached Calico Scallop. The colors are muted due to exposure and wear.
Rarity
Very Common. Calico scallops are frequently washed ashore in large quantities along certain beaches in Florida and the southeastern United States.
Habitat
Typically found in shallow marine waters, ranging from the low intertidal zone down to depths of about 150 feet. They prefer clean sandy substrates, shell rubble, and occasionally seagrass beds.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina south through Florida, the Gulf of Mexico, the Caribbean, and down to the West Indies and northern South America.
Description
A charming, fan-shaped bivalve valve featuring characteristic radial ribs and a distinctly asymmetrical ear structure near the hinge. The exterior texture is rough and slightly eroded, showing fine scaly ridges along the radiating ribs typical of the Pectinidae family.
Key Features
Rounded to slightly inequilateral fan shape, distinct radial ribs (usually around 18 to 22), unequal ears (auricles) at the hinge line, and a mottled color pattern when fresh.
Collector Value
Low collector value due to commonality and worn condition. Usually valued as a craft shell or a casual beachcombing keepsake rather than a prized cabinet specimen.
Condition Notes
Fair condition. This is a weathered, single valve missing its matching half. It shows signs of beach tumbling and UV bleaching with dull colors and smooth edges, reducing its overall collectibility grade to Fair/Good.
Interesting Facts
Unlike most bivalves that burrow or cement themselves, Calico Scallops are capable of swimming. By rapidly snapping their valves together, they expel water and propel themselves through the water column to escape predators like starfish.
Ecological Role
Calico scallops are important filter feeders, helping to clear suspended organic matter from the water column. They serve as a vital food source for numerous marine predators, including fish, rays, sea turtles, and carnivorous snails.
Similar Species
Bay Scallop (Argopecten irradians), which tends to be slightly larger with fewer, broader ribs and a more symmetrical shape, and the Rough Scallop (Aequipecten muscosus), which has more pronounced, bristly scales.
Beach Finding Tips
Look along high-tide wrack lines on sandy beaches in Florida and the Gulf Coast, particularly after storms or strong offshore winds. They are often found in large shell deposits mixed with coquina and other small bivalves.