Moon Snail or Shark Eye (Also known as Atlantic Moon Snail)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon snail family) · Gastropod (univalve, spiral shape, whole shell)
Species
Neverita duplicata (formerly Euspira duplicata or Polinices duplicatus)
Shell Type
Gastropod (univalve, spiral shape, whole shell)
Family
Naticidae (Moon snail family)
Size
Approximately 1.5 to 2 inches in diameter, which is medium-sized for this species. Adults typically range from 1 to 3 inches.
Color & Pattern
Pale cream to light grayish-brown base with subtle darker brownish shading near the low-set spire. The colors appear slightly sun-bleached from beach exposure, showing a smooth, glossy, yet worn outer porcelain-like surface.
Rarity
Common, frequently found washed ashore on sandy beaches along the Atlantic and Gulf coasts.
Habitat
Found primarily in shallow subtidal and intertidal zones, buried just beneath the surface of sandy bottoms, sandbars, and mudflats in marine environments.
Geographic Range
Western Atlantic Ocean, ranging from Massachusetts south to Florida, the Gulf of Mexico, and parts of the Caribbean.
Description
A globular, globose shell featuring a low, flattened spire and a wide, expansive body whorl. The surface is smooth with fine growth lines. While the aperture and umbilicus (which is typically filled with a characteristic dark callus in this species) are hidden in this view, the dorsal side displays the classic compact coiled apex characteristic of naticids.
Key Features
Depressed, low-profile spire, globular body whorl, smooth polished texture, and absence of prominent sculptural ribs or spines.
Collector Value
Low to moderate commercial value. While widely collected by beachcombers as a staple find, perfect specimens with intact periostracum and dark umbilical buttons are prized, though common shells generally sell for very little.
Condition Notes
Good condition. The shell is intact with minor surface wear and bleaching consistent with beach tumbling, but retains its structural integrity. Collectibility grade is Good.
Interesting Facts
Moon snails are famous carnivorous predators that drill perfectly smooth, countersunk circular holes into the shells of bivalves using an acidic secretion and a rasping radula before consuming the soft tissue inside. Their egg masses are known as 'sand collars,' formed of sand glued together with mucus.
Ecological Role
Acts as an apex invertebrate predator in soft-bottom benthic communities, regulating bivalve populations. They serve as food for various fish, birds, and larger marine predators. Not currently regulated or protected.
Similar Species
Northern Moon Snail (Euspira heros), which tends to be larger and more globose with a higher spire, and the Shark Eye (Neverita duplicata), which shares the same classification depending on current taxonomic revisions.
Beach Finding Tips
Look along sandy beaches during low tide, particularly after storms or heavy surf. Search the wash zone or look for characteristic 'sand collars' nearby in shallow water to indicate their presence.