Atlantic Calico Scallop (also known simply as the 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 1.5 to 2 inches in width and length, which is a very typical size for an adult specimen of this species. Adults generally range between 1.5 and 2.5 inches.
Color & Pattern
Displays a classic calico pattern with mottled streaks and bands of pale orange, peach, and cream against a whitish background. The coloration is entirely natural, showing gentle concentric growth rings and radiant ribs.
Rarity
Very Common. This is a very frequently encountered shell on beaches throughout its primary geographic range, especially along the Florida coast.
Habitat
Inhabits shallow marine waters, typically found on sandy or shelly bottoms, and in seagrass beds from the low intertidal zone down to depths of about 150 feet.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through the Gulf of Mexico, Florida, and the Caribbean to South America.
Description
An attractive, symmetrical bivalve featuring a classic fan shape with a well-defined umbo at the apex. The exterior surface is ornamented with roughly 18 to 22 rounded radial ribs that run from the beak to the ventral margin. The margins are slightly wavy corresponding to the external ribs, and the surface texture is finely striated.
Key Features
Rounded fan-like symmetry, approximately 18-22 prominent and smooth radial ribs, roughly equal-sized auricles (ears) at the hinge, and a distinctive mottled or banded calico coloration.
Collector Value
Low to moderate commercial value due to their abundance, but a staple and favorite for beginner and intermediate shell collectors. Specimens with exceptionally bright purple, yellow, or deep orange patterns command higher interest among color-form specialists.
Condition Notes
The specimen is in fine to good condition, mostly intact with minor wear along the ventral margin. The natural color is well preserved with minimal fading or sun-bleaching. No major boring holes or heavy encrustations are visible.
Interesting Facts
Unlike most bivalves that burrow or attach permanently to a substrate, Calico Scallops are capable of swimming short distances by rapidly clapping their valves together to expel water. They also possess dozens of simple blue eyes along the mantle edge that can detect light and shadow.
Ecological Role
Scallops are filter feeders that help maintain water clarity in coastal ecosystems. They serve as an important food source for various marine predators, including fish, rays, sea turtles, and carnivorous gastropods.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which tends to have slightly flatter shells with fewer (usually 17) and more squared ribs compared to the more rounded ribs of the Calico Scallop.
Beach Finding Tips
Look along high tide lines on sandy beaches following rough weather or strong offshore winds. They are often washed ashore in groups, particularly in areas near offshore shell beds in Florida and North Carolina.