Calico Clam (also known as the Calico Scallop or Calico Ark depending on regional nomenclature, though specifically a small venerid or lucinid bivalve)
Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Veneridae, Genus: Macrocallista, Species: maculata · Veneridae (Venus clam family) · Bivalve (two-shelled clam), whole single valve, rounded or heart-shaped disc
Species
Macrocallista maculata (Calico Clam) or related small venerid bivalve
Shell Type
Bivalve (two-shelled clam), whole single valve, rounded or heart-shaped disc
Family
Veneridae (Venus clam family)
Size
Approximately 15mm across, which is small for the species. Adults typically range from 25 to 50mm (1 to 2 inches).
Color & Pattern
Base off-white to cream color featuring a prominent, warm reddish-brown central patch or blotch. The coloration is natural and smooth, showing fine growth lines.
Rarity
Common, frequently found washed ashore on sandy beaches throughout its range.
Habitat
Shallow subtidal to intertidal zones, buried in sandy or muddy bottoms in marine environments.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina through the Caribbean Sea and down to Brazil, commonly found in Florida and Gulf of Mexico waters.
Description
A compact, rounded bivalve shell with a smooth exterior texture marked by delicate concentric growth lines. The shell features a distinctive chocolate-brown or reddish-brown central coloration contrasting against a pale, creamy background. The margins are smooth and the overall shape is subtly oval to heart-shaped.
Key Features
Small, solid, oval-to-rounded valve with smooth concentric lines and a characteristic centralized brown patch or blotch on a pale background.
Collector Value
Low to moderate commercial value, primarily collected by hobbyists and beachcombers rather than advanced shell collectors, usually valued at under a dollar per specimen.
Condition Notes
Good condition whole single valve with natural coloration preserved, minor smoothing from wave action, graded as Good to Fine collectibility.
Interesting Facts
Venerid clams are filter feeders that use muscular siphons to draw in water and extract microscopic algae and nutrients from the surrounding sediment.
Ecological Role
Serves as an important food source for bottom-feeding fish, rays, and carnivorous gastropods, while helping to bioturbate sandy sediments through burrowing activity.
Similar Species
Other small venus clams and lucines, distinguished primarily by hinge structure, exact proportions, and specific internal ribbing or pallial line features.
Beach Finding Tips
Look along high-tide shell lines on sandy tropical or subtropical beaches, especially following stormy weather or rough surf conditions.