Magpie Shell or Cockscomb Cockle
Phylum Mollusca, Class Bivalvia, Order Cardiida, Family Cardiidae, Genus Trachycardium, Species T. egmontianum · Cardiidae (Cockle family) · Bivalve, whole shell valve, fan shape
Species
Trachycardium egmontianum
Shell Type
Bivalve, whole shell valve, fan shape
Family
Cardiidae (Cockle family)
Size
Approximately 0.75 inches, which is on the smaller side. Adults typically range from 1 to 2 inches.
Color & Pattern
Cream to white base with vibrant reddish-orange to brown blotches and spots concentrated along the prominent radial ribs and posterior margin. Colors appear natural and well-preserved.
Rarity
Common, frequently found by dedicated beachcombers in its native range.
Habitat
Shallow subtidal zones, sandy and muddy substrates, often found in bays and nearshore marine environments.
Geographic Range
Western Atlantic, from North Carolina through Florida, the Gulf of Mexico, and the Caribbean.
Description
A charming and sturdy bivalve shell featuring strong, elevated radial ribs adorned with distinctive scalelike projections or knobs. The margin is deeply scalloped to match the ribs, giving it a rugged, textured appearance.
Key Features
Prominent, rough radial ribs with distinct nodes or scales along the crests, combined with reddish-orange spotting on a pale background.
Collector Value
Low to moderate commercial value, popular among beginner and intermediate shell collectors for its bright colors and sculptural texture.
Condition Notes
Good condition with minor wear on the margins, natural coloration largely intact, graded as Fine collectibility.
Interesting Facts
Cockles use a muscular, axe-like foot to burrow rapidly into the sand and even to leap away from predators like starfish.
Ecological Role
Acts as an important food source for marine predators such as rays, large gastropods, and crabs, while filtering suspended particles from the water column.
Similar Species
Prickly Cockle (Trachycardium muricatum), which tends to be larger and has more delicate, numerous spines.
Beach Finding Tips
Look along high-tide lines on sandy Gulf and Atlantic beaches, especially after storms or heavy wave action.