Rigid Venus, Imperial Venus, or Speckled Venus
Kingdom: Animalia, Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Veneridae, Genus: Globivenus, Species: G. rigida · Veneridae (Venus Clam family) · Bivalve (single valve shown). Sub-globose/circular fan shape.
Species
Globivenus rigida (formerly Venus rigida)
Shell Type
Bivalve (single valve shown). Sub-globose/circular fan shape.
Family
Veneridae (Venus Clam family)
Size
Approximately 1.5 to 2.5 inches (40-60mm). This specimen appears to be an average-sized adult for the genus.
Color & Pattern
Dull white to grayish-tan base with weathered brown/purplish markings. The exterior shows faint radial streaks and concentric brownish blotches. The shell appears sun-bleached and calcified, losing much of the natural luster.
Rarity
Common to Uncommon. While the species is not rare, finding a beach-washed specimen in perfect condition is less common than finding worn valves.
Habitat
Subtidal marine environments; typically found in sandy bottoms, rubble, or coral reef margins at depths of 10 to 100 meters.
Geographic Range
Western Atlantic: Florida to South Carolina, Bermuda, the Caribbean Sea, and south to Brazil.
Description
A sturdy, thick-walled bivalve characterized by its globose, rounded shape. The sculpture consists of numerous, prominent, crowded concentric ridges that are slightly irregular. The exterior has a rough, sandy texture due to weathering. The edges are finely crenulated on the interior margin.
Key Features
Highly convex (inflated) valves, extremely heavy and thick shell for its size, and coarse, closely spaced concentric ridges without strong radial ribs.
Collector Value
Low to Moderate ($2-$10 USD). Weathered single valves have little commercial value, but a paired set of 'Gem' condition shells with full color can be desirable for regional specialists.
Condition Notes
Fair. This is a beach-worn specimen showing significant erosion and loss of sharp detail on the ridges. It is a single valve (dead shell) with some calcification and minor chipping on the edges. Not a 'Gem' specimen, but a good representative of a weathered find.
Interesting Facts
The Veneridae family is one of the largest families of clams. Many species in this family, like the Rigid Venus, are known for their exceptional shell thickness, which protects them from crushing predators like rays and certain sea stars.
Ecological Role
Suspension feeder that filters plankton from the water column. Its thick shells provide a substrate for encrusting bryozoans and algae after the animal dies.
Similar Species
Lirophora paphia (King Venus) which has much thicker, prominent ribs; or Mercenaria mercenaria (Quahog) which lacks the distinct raised concentric sculpture.
Beach Finding Tips
Look along the wrack line after heavy storms or high surf in the Florida Keys or Caribbean. They are often found partially buried in shell hash due to their weight.