Cross-hatched Lucine (also known as the Weaving Lucine)
Phylum: Mollusca, Class: Bivalvia, Order: Lucinida, Family: Lucinidae, Genus: Divalinga, Species: Divalinga quadrisulcata · Lucinidae (Lucine Clams) · Bivalve (Single Valve); shape is sub-circular to orbicular with a distinctive divaricate (criss-cross) sculpture.
Species
Divalinga quadrisulcata (90% confidence based on hinge orientation and sculpture)
Shell Type
Bivalve (Single Valve); shape is sub-circular to orbicular with a distinctive divaricate (criss-cross) sculpture.
Family
Lucinidae (Lucine Clams)
Size
Approximately 0.5 to 0.75 inches (12-19mm). This is typical for a juvenile or small adult; the species maxes out around 1 inch.
Color & Pattern
Predominantly chalky white to off-white. This specimen shows slight gray/brownish staining near the umbo (beak), likely from mineral absorption in the sediment. It lacks vibrant patterns, focusing instead on structural texture.
Rarity
Common. These are frequently found on beaches throughout the Atlantic and Caribbean, though their small size makes them easy to overlook.
Habitat
Shallow marine environments, typically buried in sandy or muddy substrates. They are common in intertidal zones and shallow subtidal waters.
Geographic Range
Western Atlantic, ranging from Massachusetts down to Florida, the Gulf of Mexico, the Caribbean, and south to Brazil.
Description
A beautiful, small, sturdy bivalve characterized by a unique 'chevron' or 'cross-hatched' sculptural pattern. The surface lacks the concentric growth rings typical of most clams, instead featuring fine, diagonal ridges that meet at an angle along a central axis. The shell is moderately inflated (rounded) and has a clean, matte finish when dry.
Key Features
The defining trait is the divaricate sculpture—ridges that run diagonally and intersect. It also features a small, inconspicuous beak (umbo) and finely serrated inner margins (if viewed from the interior).
Collector Value
Low monetary value (usually less than $1) due to abundance. However, they are highly desirable for 'miniature' collectors and those who appreciate geometric biological patterns. Often used in shell art and jewelry.
Condition Notes
Condition is Fair to Good. The shell is a single valve (not a complete matched pair). It shows some 'beach wear'—softened edges and slight erosion of the sharpest ridges. No visible predator bore holes. Grade: Good/Commercial.
Interesting Facts
Lucine clams are biologically fascinating because they host symbiotic sulfur-oxidizing bacteria in their gills. These bacteria convert hydrogen sulfide from the sediment into nutrients for the clam, allowing them to thrive in environments where food is scarce.
Ecological Role
As burrowing filter feeders, they help oxygenate the substrate. Their symbiosis with bacteria makes them important players in the sulfur cycle of seagrass beds and sandy flats.
Similar Species
Lucina pensylvanica (Pennsylvania Lucine) which has deeper concentric grooves, and Divaricella dentata which is larger with more pronounced 'teeth' on the margins.
Beach Finding Tips
The best time to find these is at low tide in the 'shell hash' or drift line. Because they are light, they often wash up further up the beach than heavier shells. Look for the 'criss-cross' texture glinting in the sun.