Shark Eye, Atlantic Moon Snail
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon snail family) · Gastropod (univalve); whole shell; globular/spiral shape.
Species
Neverita duplicata (likely, 95% confidence)
Shell Type
Gastropod (univalve); whole shell; globular/spiral shape.
Family
Naticidae (Moon snail family)
Size
Approximately 1.5 to 2 inches in diameter. Adults typically reach 2 to 3.5 inches, making this a mid-sized juvenile or small adult.
Color & Pattern
Predominantly tan to grayish-brown with a darker slate-blue or grey spiral near the apex (the 'eye'). The base color is natural but shows some surface wear. The underside (not fully visible) usually contains a large, chestnut-brown callus covering the umbilical area.
Rarity
Very Common; frequently found after storms or during low tide on Atlantic beaches like Holden Beach.
Habitat
Marine; intertidal and shallow subtidal zones. Prefers sandy substrates where it can burrow to hunt for prey.
Geographic Range
Western Atlantic coast from Massachusetts to Florida and the Gulf of Mexico. This specimen is highly consistent with finds from the Carolinas.
Description
A smooth, round, globular shell with a low, flattened spire. The surface is polished and lacks heavy ornamentation. The whorls expand rapidly, ending in a large body whorl. The 'eye' at the center of the spire is its most diagnostic visual feature, looking like a dark pupil against a lighter background.
Key Features
Globular/depressed shape; dark grey-blue apex; large chestnut-brown umbilical callus; smooth, porcelain-like texture; rapid expansion of the last whorl.
Collector Value
Low monetary value ($1-$5) but highly desirable for beginners and beachcombers due to its aesthetic 'eye' and smooth feel. Gem specimens with a perfect glossy finish are more prized.
Condition Notes
Good. The shell is structurally intact but shows 'beach-worn' characteristics including fine surface abrasions and minor loss of luster. The spire is well-preserved, though the outer layer shows slight calcium erosion from sand tumbling.
Interesting Facts
Moon snails are predatory 'drilling' snails. They use their radula and an acid-secreting gland to drill perfectly circular holes in other bivalves. They also create 'sand collars'—fragile, circular egg cases made of sand and mucus that look like discarded rubber gaskets.
Ecological Role
Significant apex predator among benthic invertebrates. They control populations of clams and mussels. They are also sensitive to changes in sandy barrier island ecosystems.
Similar Species
Euspira heros (Northern Moon Snail), which is larger, more globose, lacks the large dark callus, and generally has a northern distribution.
Beach Finding Tips
Scan the wrack line after a high tide or explore sand flats during extreme low tides. Look for the distinctive circular shape poking through the sand or among clusters of heavier shells like whelks.
Notes
Holden Beach, NC