Cross-hatched Lucine
Phylum: Mollusca, Class: Bivalvia, Order: Lucinida, Family: Lucinidae, Genus: Divalinga, Species: quadrisulcata · Lucinidae (Lucine Clam family) · Bivalve (clams, oysters, mussels); single valve (left valve); circular/sub-orbicular shape.
Species
Divalinga quadrisulcata
Shell Type
Bivalve (clams, oysters, mussels); single valve (left valve); circular/sub-orbicular shape.
Family
Lucinidae (Lucine Clam family)
Size
Approximately 0.75 to 1.0 inches (19-25mm). This is typical for a mature specimen of this species, which generally grows to a maximum of about 1.25 inches.
Color & Pattern
Translucent white to creamy off-white. The color is largely uniform and natural for the species. It lacks pigmented patterns, relying instead on its structural surface texture for visual interest. The interior is generally white and slightly glossy.
Rarity
Common. They are frequently found by beachcombers on South Carolina beaches, though their small size and white color often make them blend in with shell hash.
Habitat
Marine; found in shallow subtidal waters and intertidal zones. They typically live buried in sandy or muddy substrates in warm temperate and tropical waters.
Geographic Range
Western Atlantic from New Jersey to Florida, the Gulf of Mexico, the Caribbean, and south to Brazil. This specimen from Myrtle Beach, SC, is centrally located within its typical range.
Description
A beautiful, small, circular bivalve known for its unique 'cross-hatched' or divaricating sculptural pattern. The shell is moderately convex with a prominent umbo (beak) that points forward. The surface is covered in fine, sharp, chevron-like ridges that meet at an angle along a central line, giving it a texture reminiscent of a fabric weave or tool marks.
Key Features
The diagnostic feature is the 'divaricating' sculpture—ridges that run obliquely across the shell rather than concentrically or radially. This creates a distinct 'V' or 'chevron' pattern that is unmistakable among Western Atlantic bivalves.
Collector Value
Low monetary value (~$1-$5) but high aesthetic interest. It is a staple of 'beach house' collections and a favorite for amateur conchologists due to its intricate geometric texture.
Condition Notes
Good condition. The shell appears mostly intact with sharp sculpture. There is a small hole near the center, likely a 'drill hole' from a predatory moon snail (Naticidae) or oyster drill. The color is well-preserved and not significantly beach-worn. Grade: Fine.
Interesting Facts
Lucine clams are known for a fascinating symbiotic relationship: they host sulfur-oxidizing bacteria in their gills. These bacteria convert hydrogen sulfide from the sediment into energy for the clam, allowing them to survive in oxygen-poor environments where other mollusks might struggle.
Ecological Role
As a filter feeder and a host for chemoautotrophic bacteria, it plays a vital role in nutrient cycling in sandy ecosystems. It is a primary prey item for predatory gastropods (evidenced by the drill hole in this specimen). It is not currently protected or endangered.
Similar Species
The Divergent Lucine (Lucinoma species) or the Tiny Lucine (Parvilucina multilineata). However, Divalinga quadrisulcata is distinguished by the specific sharpness and angle of its cross-hatched ridges.
Beach Finding Tips
Scan the drift line after a high tide, particularly in areas with fine shell grit. Because they are light, they are often pushed to the very top of the tide line. Look for a 'pure white' circular shape among the darker fragments.
Notes
Myrtle Beach in SC