Cross-hatched Lucine (also known as the Crib Lucine)
Kingdom: Animalia; Phylum: Mollusca; Class: Bivalvia; Order: Lucinida; Family: Lucinidae; Genus: Divalinga; Species: Divalinga quadrisulcata · Lucinidae (Lucine clams) · Bivalve (single valve); sub-circular/orbicular shape
Species
Divalinga quadrisulcata (95% confidence based on Cancun locality and distinctive sculpture)
Shell Type
Bivalve (single valve); sub-circular/orbicular shape
Family
Lucinidae (Lucine clams)
Size
Approximately 18-22mm in diameter. This is a mature specimen, as the species typically ranges from 15mm to 25mm.
Color & Pattern
Uniformly chalky white to creamy white. The specimen appears slightly sun-bleached but retains its natural matte finish. There are no patterns or bands, as the species is monochromatic.
Rarity
Common (found regularly on beaches throughout the Caribbean and Gulf of Mexico).
Habitat
Infaunal (living buried in sediment); found in intertidal and shallow subtidal zones in sandy or muddy substrates, often near seagrass beds.
Geographic Range
Western Atlantic: Massachusetts to Florida, Bermuda, Gulf of Mexico, and the Caribbean (including Cancun, Mexico) to Brazil.
Description
A beautiful, small, disc-shaped bivalve characterized by its unique 'divaricate' sculpture. The shell is solid and moderately convex. The most striking feature consists of fine, sharp, chevron-like ridges that cross the growth lines at an angle rather than radiating from the hinge. This creates a cross-hatched or 'shingled' texture that is pleasing to the touch.
Key Features
Distinctive divaricate (zigzag) sculpture that meets at an angle along a central line; rounded, orbicular shape; small, inward-pointing beaks (umbones); a well-defined internal ligament.
Collector Value
Low monetary value ($1-$3) due to its abundance, but highly desired by amateur collectors because of its unique geometric texture. It is a 'must-have' for a representative Caribbean bivalve collection.
Condition Notes
Good; the valve is intact with a sharp edge, though it shows some minor surf-wear on the sculpture. It lacks the original gloss of a live-taken specimen but is a perfect representative of a beach-found valve. Collectibility: Fine.
Interesting Facts
Members of the Lucinidae family are fascinating because they host symbiotic chemoautotrophic bacteria in their gills. These bacteria oxidize hydrogen sulfide from the sediment to provide nutrients to the clam, allowing them to thrive in oxygen-poor environments where other mollusks might struggle.
Ecological Role
Benthic filter feeders and bacterial hosts; they play a critical role in nutrient cycling within sandy marine ecosystems and help manage sulfide levels in the sediment.
Similar Species
Lucina pensylvanica (Pennsylvania Lucine), which has a more prominent fold/groove on the posterior side and lacks the sharp zigzag divaricate ridges.
Beach Finding Tips
In Cancun, look in the 'shell hash' lines left by the receding tide, particularly after a period of moderate surf. Because they are light and flat, they often stay near the surface of the sand piles.
Notes
Cancun