Cross-hatched Lucine (also known as the Weave Lucine)
Phylum: Mollusca, Class: Bivalvia, Order: Lucinida, Family: Lucinidae, Genus: Divalinga, Species: quadrisulcata · Lucinidae (Lucine Clams) · Bivalve; single valve (left); circular/sub-globose shape.
Species
Divalinga quadrisulcata
Shell Type
Bivalve; single valve (left); circular/sub-globose shape.
Family
Lucinidae (Lucine Clams)
Size
Approximately 1.8-2.0 cm in diameter based on the provided scale. This is a mature specimen; the species typically ranges from 1.5 cm to 2.5 cm.
Color & Pattern
Predominantly white to chalky grey. This specimen appears weathered or sub-fossilized, losing its original translucent white luster. It shows concentric growth lines overlaid by its signature divergent sculpture.
Rarity
Common to Very Common. These are frequently found on beaches throughout the Caribbean and the Southeastern United States.
Habitat
Marine; typically found in shallow subtidal waters and intertidal zones, buried in sandy or muddy substrates, often near seagrass beds.
Geographic Range
Western Atlantic: Massachusetts to Florida, Bermuda, Gulf of Mexico, and the West Indies down to Brazil.
Description
A small, sturdy, orbicular bivalve characterized by a unique 'chevron' or 'cross-hatched' sculptural pattern. The surface is covered in fine, sharp grooves that dive at an angle, meeting along a central axis to form a V-shape. The shell is moderately inflated with a small, slightly curved beak (umbo).
Key Features
The diagnostic feature is the 'divaricate' sculpture—oblique grooves that cross growth lines to form a distinct weave or lattice pattern, which is unique among western Atlantic bivalves of this size.
Collector Value
Low. While aesthetically pleasing due to the pattern, it is a very common beach find. It holds more value as an educational specimen or as part of a regional biodiversity set. Approx value: <$1.00.
Condition Notes
Fair to Good. The shell is intact with no major chips, but it shows significant environmental weathering and loss of natural sheen. The periostracum is absent, and the color has dulled to a matte grey-white.
Interesting Facts
Lucine clams are famous for their symbiotic relationship with chemoautotrophic bacteria living in their gills. These bacteria oxidize hydrogen sulfide from the sediment to provide nutrients for the clam, allowing it to survive in low-oxygen environments.
Ecological Role
Infaunal filter feeder and sulfur-oxidizer. By processing hydrogen sulfide, they help detoxify the sediment around seagrass roots, playing a vital role in maintaining healthy coastal ecosystems.
Similar Species
Divalinga dentata (larger, with more pronounced serrations on the margin) and various species of the genus Lucina (which lack the diagonal 'weave' sculpture).
Beach Finding Tips
Look in the 'shell hash' lines at low tide on sandy Atlantic beaches. Because they are small and white, they are often overlooked among larger broken shells. They are most common after storms that disturb the shallow sandy bottom.