Common Egg Cockle (also known as the Yellow Cockle)
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Cardiidae, Genus: Trachycardium, Species: Trachycardium egmontianum · Cardiidae (Cockle family) · Bivalve, whole shell, roughly heart-shaped fan
Species
Trachycardium egmontianum
Shell Type
Bivalve, whole shell, roughly heart-shaped fan
Family
Cardiidae (Cockle family)
Size
Approximately 1.5 to 2 inches in width, which is typical for a mature specimen of this species. Adults generally range from 1 to 2.5 inches.
Color & Pattern
Yellowish-brown to creamy white base color with darker brown or purplish-brown mottling and radial streaks. The colors are natural and vibrant with a glossy sheen near the umbo.
Rarity
Common
Habitat
Shallow subtidal marine waters, typically found buried just beneath the surface in sandy bottoms, sandbars, and seagrass beds.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through Florida, the Gulf of Mexico, and the Caribbean Sea.
Description
A sturdy, attractive bivalve featuring prominent, sharp radial ribs that interlock neatly at the margin. The shell has a distinctive heart-shaped profile when viewed from the side and a very prominent, curved umbo.
Key Features
Strongly inflated valves with 30 to 40 distinct, scaly or bumpy radial ribs and a serrated ventral margin.
Collector Value
Low to moderate commercial value, but highly popular among casual beachcombers and specialized bivalve collectors due to its striking symmetry and sculptural ribs.
Condition Notes
Good condition with intact margins, vibrant natural color, and minimal wear on the prominent ribs. Collectibility grade is Fine.
Interesting Facts
Cockles are capable of a surprising form of locomotion; using their muscular, sickle-shaped foot, they can leap or flip themselves away from predators like starfish.
Ecological Role
Serves as an important prey item for various marine predators including sea stars, carnivorous gastropods, and fish, while filtering organic particles from the water column.
Similar Species
Prickly Cockle (Trachycardium muricatum), which tends to have sharper, more pronounced spines on the ribs and a slightly different geographic preference.
Beach Finding Tips
Look along sandy Gulf and Atlantic beaches following strong storms or during extreme low tides, scanning the surf line where whole bivalves are washed ashore.