Atlantic Cockle (also known as Common Cockle)
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Cardiidae, Genus: Dinocardium, Species: D. robustum · Cardiidae (Cockle family) · Bivalve (two-shelled), whole shell, fan or heart shape
Species
Dinocardium robustum
Shell Type
Bivalve (two-shelled), whole shell, fan or heart shape
Family
Cardiidae (Cockle family)
Size
Approximately 2 to 2.5 inches in width, which is a medium-sized specimen for this species. Adults typically range from 2 to 5 inches.
Color & Pattern
Cream to pale yellow base color with subtle brownish-orange or reddish speckling and banding, especially near the umbo and margins. Colors appear mostly natural with slight sun-bleaching.
Rarity
Common, frequently found by beachcombers along the southeastern United States and Gulf coasts.
Habitat
Shallow subtidal and intertidal zones, typically burrowing in clean fine sand or muddy sand environments in marine waters.
Geographic Range
Western Atlantic Ocean, ranging from Virginia down through Florida, the Gulf of Mexico, and the Caribbean.
Description
A robust, inflated bivalve shell with deep radial ribs and a distinctive heart-shaped profile when viewed from the side. The margins are strongly scalloped to interlock tightly, and the exterior features prominent, rounded ribs radiating from the umbo.
Key Features
Strongly inflated valves, prominent and numerous radial ribs (usually around 32 to 36), asymmetrical heart-shaped profile, and interlocking serrated margins.
Collector Value
Inexpensive and widely available, typically collected as a souvenir rather than bought, with individual specimens valued under a few dollars.
Condition Notes
Good condition with intact margins and minimal wear. Minor natural sun-bleaching and slight wear on the umbo. Collectibility grade: Good.
Interesting Facts
Cockles are capable of remarkable leaps using their strong, muscular foot to escape predators like starfish and predatory snails.
Ecological Role
Acts as a filter feeder helping to clear suspended organic matter from the water column, serving as an important prey item for crabs, rays, and carnivorous gastropods.
Similar Species
Magnum Cockle (Dinocardium magnum), which tends to be larger and more elongated with sharper color banding.
Beach Finding Tips
Look along high tide lines on sandy beaches of the Gulf of Mexico and Florida after storm events or rough surf.