Calico Scallop (also known as the Atlantic Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell, asymmetrical fan shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole shell, asymmetrical fan shape
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches in length and width, which is average for this species. Adults typically range from 1.5 to 3 inches.
Color & Pattern
Featuring a mottled and patterned exterior with warm reddish-brown and chocolate-brown zigzag bands and splashes against a creamy white or off-white base. The coloration is natural and vibrant, showing minimal sun-bleaching.
Rarity
Common, frequently washed up on beaches throughout its range, particularly following storms.
Habitat
Marine environment, typically found in shallow subtidal waters down to about 150 feet, residing on sandy or shelly substrates, often among seagrass beds.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina through the Gulf of Mexico, Florida, and the Caribbean to South America.
Description
An attractive, stoutly inflated bivalve shell with distinct radial ribs and characteristic asymmetrical ears at the hinge. The outer surface is beautifully adorned with rich brown zig-zag markings over a cream background. The margins are crenulated to match the external ribs, creating a tightly sealed closure when both valves are present.
Key Features
Unequal 'ears' (auricles) at the hinge line, one side being longer than the other, which is a hallmark of the genus Argopecten, combined with strong radial ribs and characteristic mottled brown and white coloration.
Collector Value
Low to moderate commercial and collector value. They are very popular for shell crafts, decorations, and beginner shell collections due to their bright patterns, but common specimens hold modest monetary value (typically under a dollar individually).
Condition Notes
Good to Fine condition. The shell is intact with natural coloration mostly preserved, though it exhibits a small natural growth hole or predator bore near the upper center. Minor edge wear from tumbling in the surf.
Interesting Facts
Unlike most bivalves that burrow or remain sessile, calico scallops are capable of swimming by rapidly clapping their valves together to expel water, allowing them to escape predators like starfish and crabs.
Ecological Role
Calico scallops serve as an important prey base for carnivorous marine animals including rays, sea stars, large gastropods, and seabirds. They are filter feeders that help clear particulate matter from the water column.
Similar Species
Bay Scallop (Argopecten irradians), which tends to be slightly larger with fewer, flatter ribs and a more rounded, symmetrical profile.
Beach Finding Tips
Look along ocean-facing beaches in Florida and the southeastern United States, particularly at low tide or immediately following heavy onshore winds and tropical storms.