Sunray Venus Clam
Kingdom: Animalia, Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Veneridae, Genus: Macrocallista, Species: M. nimbosa · Veneridae (Venus Clam family) · Bivalve (Clam/Two-shelled); elongated oval or elliptical shape. This specimen is a whole shell with both valves joined.
Species
Macrocallista nimbosa (Confidence: 95%)
Shell Type
Bivalve (Clam/Two-shelled); elongated oval or elliptical shape. This specimen is a whole shell with both valves joined.
Family
Veneridae (Venus Clam family)
Size
Approximately 3 to 4 inches (75-100mm) in length. This is an average adult size; the species can reach up to 6 inches.
Color & Pattern
Base color is a warm tan to lilac-gray. Features distinctive radiating purplish-brown sunray bands extending from the umbo (beak) to the margins. Interior is typically smooth and white with a dull purple wash.
Rarity
Common. This species is frequently found on sandy beaches after storms or high tides, though finding both valves still attached (as seen here) is less common than single valves.
Habitat
Shallow subtidal marine environments. Prefers clean, sandy substrates from the low tide mark to depths of about 30 feet. Frequently found in high-salinity bays and open coastal waters.
Geographic Range
Western Atlantic; ranging from North Carolina down through Florida and the Gulf of Mexico to the West Indies.
Description
A sleek, elongated bivalve known for its glossy, porcelain-like finish. The shell is sturdy and Relatively thin but strong, with a smooth surface marked only by fine concentric growth lines. The valves are symmetrical and close tightly, featuring a dark, prominent external ligament near the hinge.
Key Features
Distinctive elongated elliptical shape (much longer than wide); radiating 'sunray' color pattern; smooth, glossy exterior texture; 'hinge' area located toward one end rather than centered.
Collector Value
Low to Moderate ($2 - $10 USD). While common, specimens with both valves intact and vibrant sunray patterns are staple items for regional Florida/Atlantic collectors and are highly desirable for coastal craft use.
Condition Notes
Fine to Good. The shell retains its natural color and sheen. The valves are articulated (joined), which increases collectibility. Minor edge wear is visible, and the exterior shows natural matte weathering common in beach-tossed specimens.
Interesting Facts
Living Sunray Venus clams are active burrowers using a powerful muscular foot. Historically, Native American tribes in Florida used these shells as scrapers and occasionally as spoons or small bowls due to their smooth, shallow shape.
Ecological Role
Suspension feeder that filters plankton from the water column. They serve as a vital food source for gastropods like Lightning Whelks and moon snails, as well as for rays and shorebirds.
Similar Species
Macrocallista maculata (Calico Clam), which is much shorter, more squared, and features a checkered/checkerboard pattern rather than radiating rays.
Beach Finding Tips
Best found on Florida's Gulf Coast (e.g., Sanibel/Captiva) after strong westerly winds. Look along the low-tide line in areas with fine sand rather than shell-hash piles.