Common Egg Cockle, also known as the Smooth Egg Cockle or Elegant Cockle.
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Cardiidae, Genus: Laevicardium, Species: Laevicardium elatum. · Cardiidae (Cockle family). · Bivalve (Two-shelled). The specimen shown is a single valve with a rounded, inflated shape.
Species
Laevicardium elatum (confidence level 85% based on morphology; potentially Laevicardium laevigatum).
Shell Type
Bivalve (Two-shelled). The specimen shown is a single valve with a rounded, inflated shape.
Family
Cardiidae (Cockle family).
Size
Estimated at 1 to 1.5 inches in length. This is small for the species, as giants can reach 6 inches; it is likely a juvenile or a smaller relative like L. laevigatum.
Color & Pattern
Uniform creamy white to pale yellow. The exterior appears slightly sun-bleached or weathered, lacking the typical high-gloss yellow periostracum often found in live-collected specimens. No distinct banding is visible.
Rarity
Common. These shells are frequently washed up on beaches, though finding a perfectly paired set of valves is less common than finding single valves.
Habitat
Marine; typically found in shallow subtidal waters to depths of 30 meters. They prefer offshore sandy bottoms or mud flats where they can burrow.
Geographic Range
Western Atlantic from North Carolina to the West Indies and Brazil; also common in the Gulf of California to Panama.
Description
A smooth, egg-shaped bivalve valve with a notably inflated (convex) profile. Unlike most cockles that have deep radial ribs, this genus is characterized by a nearly smooth surface with very faint, fine radial lines. The shell is sturdy and porcelain-like.
Key Features
Smooth exterior surface, lack of heavy ribs, inflated 'egg-like' shape, and a curved beak (umbo). The interior hinge usually features small teeth typical of the cockle family.
Collector Value
Minimal ($1 - $5). This is a common beach find. Value increases significantly for large, 'gem' quality specimens with both valves attached and the yellow periostracum intact.
Condition Notes
Fair to Good. The shell shows signs of beach wear (rounded edges) and possible sun-bleaching. The surface luster has been dulled by sand abrasion. It is a single valve rather than a 'double'. Grade: Commercial/Study grade.
Interesting Facts
The living animal has a very strong, muscular foot that it uses to 'jump' across the seafloor to escape predators like sea stars. Historically, these smooth shells were polished and used in jewelry or as decorative inlays.
Ecological Role
Suspension feeders that filter plankton from the water column. They serve as a vital food source for rays, sea stars, and larger gastropods. They help aerate the substrate through burrowing.
Similar Species
Laevicardium laevigatum (smaller, more colorful) and Fulvia tenuicostata. It differs from the Atlantic Strawberry Cockle by its lack of bumps and bright red colors.
Beach Finding Tips
Look along the high-tide line after a storm. They are often partially buried in the sand. Best found on wide, sandy beaches in Florida, the Caribbean, or the Gulf of California.