Calico Scallop (also known as the Pecten)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole individual valve, fan or circular shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole individual valve, fan or circular shape
Family
Pectinidae (Scallop family)
Size
Approximately 0.5 to 1 inch, which is smaller than average or a juvenile specimen. Adult Calico Scallops typically range from 1.5 to 2.5 inches.
Color & Pattern
Displays a mottled and marbled pattern of warm reddish-brown, orange, and white patches typical of the calico variety. The colors are natural and vibrant, showing radial ribs extending from the umbo to the outer margin.
Rarity
Very Common, frequently washed up intact on beaches throughout its native range, especially along the southeastern coast of the United States and the Gulf of Mexico.
Habitat
Shallow marine waters, typically found in sandy or muddy substrates, seagrass beds, and offshore shoals in subtidal zones ranging from shallow water down to about 160 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through Florida, the Gulf of Mexico, and the Caribbean Sea.
Description
A charming and compact bivalve shell featuring a classic fan shape with strongly defined, rounded radial ribs. The exterior showcases an attractive patchwork of mottled orange, brown, and cream hues. The surface is textured with fine growth lines crossing the prominent ribs, and the ventral margin is scalloped to match the internal ribbing.
Key Features
Equivalve to slightly inequivalve rounded fan shape, prominent and rounded radial ribs (usually around 18 to 22), well-developed auricles (ears) at the hinge line, and colorful mottled patterns.
Collector Value
Low to moderate value for individual specimens as they are very common, though they are popular in craft projects and beginner collections. Typically worth only a few cents to a dollar.
Condition Notes
The shell appears to be in Good to Fine condition, intact with bright natural coloration and minimal wear on the margins, making it a pleasant specimen for casual collection.
Interesting Facts
Unlike many other bivalves that burrow or attach permanently, Calico Scallops are capable of swimming short distances by rapidly clapping their valves together to expel water, using a series of dozens of simple blue eyes along their mantle edge to detect light and shadow.
Ecological Role
Serves as an important prey item for various marine predators including fish, rays, sea turtles, and crabs. They filter feed on phytoplankton, helping to maintain water clarity in coastal ecosystems.
Similar Species
Bay Scallop (Argopecten irradians), which tends to be slightly larger with flatter ribs, and the Atlantic Deep-Sea Scallop (Placopecten magellanicus), which is much larger and lacks the vibrant calico patterning.
Beach Finding Tips
Look along the wrack line on high-energy sandy beaches after a storm or incoming high tide, particularly in Florida and North Carolina where shell fragments and whole valves wash ashore in abundance.