Coquina Clam (or Butter Clam)
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Tellinidae, Genus: Macoma, Species: Macoma tenta · Tellinidae (Tellin family) · Bivalve (two-shelled clam), whole single valve, oval-elongate shape
Species
Macoma tenta or similar Macoma species (likely an asymmetric tellin or macoma)
Shell Type
Bivalve (two-shelled clam), whole single valve, oval-elongate shape
Family
Tellinidae (Tellin family)
Size
Approximately 2 inches in length, which is slightly larger than average for many local macoma species, which typically range from 1 to 2.5 inches.
Color & Pattern
Off-white to creamy base color with soft yellowish-tan bands and growth lines. The colors appear slightly sun-bleached and worn from wave action, typical of beach-found specimens.
Rarity
Very Common
Habitat
Inhabits soft-bottom marine and estuarine environments, burrowing into sand or mud flats in intertidal to shallow subtidal zones.
Geographic Range
Western Atlantic Ocean, extending along the North American coast from Canada down to Florida and the Gulf of Mexico, commonly found in the Outer Banks of North Carolina.
Description
An oval-shaped, slightly elongated bivalve shell with concentric growth lines tracing its contour. The exterior features a smooth texture with subtle weathering and a gentle curve near the posterior end. The margins are intact though showing signs of gentle tumbling in the surf.
Key Features
Smooth, elongated oval outline, prominent concentric growth rings, a slightly upturned or twisted posterior end (characteristic of many tellins and macomas), and a lack of heavy radial ribs.
Collector Value
Low commercial value as they are extremely common beach finds, but prized by casual beachcombers and crafters.
Condition Notes
Good condition. The shell is a complete single valve with some surface wear and minor edge chipping from wave action, but retains its structural integrity and natural coloration.
Interesting Facts
Macoma clams are deposit feeders, using their long, separate siphons to vacuum up organic detritus from the surface of the sediment while buried safely beneath the sand.
Ecological Role
Serves as an important food source for shorebirds, crabs, and bottom-feeding fish, while helping to cycle nutrients in benthic marine environments.
Similar Species
Other tellins such as the Northern Tellin (Tellina agilis) or various ark clams, which can be distinguished by heavier ribbing or more symmetrical, rounded shapes.
Beach Finding Tips
Look along the high tide line or in shell piles after a storm or strong onshore winds, particularly on sandy ocean-facing beaches like those in the Outer Banks.
Notes
Outer banks, North Carolina on Kill Devils Hill beach