Shark Eye Moon Snail (also known as the Northern Moon Snail or Atlantic Moon Snail)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: N. duplicata · Naticidae (Moon Snail family) · Gastropod (univalve) with a globose or spiral shape
Species
Neverita duplicata (formerly Polinices duplicatus)
Shell Type
Gastropod (univalve) with a globose or spiral shape
Family
Naticidae (Moon Snail family)
Size
Approximately 2 to 2.5 inches in diameter, which is a medium-to-large size for this species. Adults typically range from 1.5 to 3 inches.
Color & Pattern
The base color is creamy white to light grayish-tan, featuring characteristic brownish-purple flame-like streaks or banding radiating downward from the suture, and a darker purple-brown patch near the umbilicus area. The colors appear generally natural with slight weathering.
Rarity
Common, frequently found washed ashore along sandy coastlines.
Habitat
Found primarily in shallow subtidal and intertidal zones, buried just beneath the surface of sandy bottoms, mudflats, and sandbars in marine environments.
Geographic Range
Western Atlantic Ocean, ranging from Massachusetts down to the Gulf of Mexico, Brazil, and parts of the Caribbean.
Description
A globular, smooth, and glossy univalve shell with a low, flattened spire and a rapidly expanding final body whorl. The surface is mostly smooth with fine growth lines, featuring a characteristic wide callus covering the umbilicus region on the underside.
Key Features
Low spire, globose shape, smooth polished surface, and a heavy callus (button) that partially or completely covers the umbilical area.
Collector Value
Low to moderate commercial value; very popular among casual beachcombers and beginner shell collectors due to their pleasing symmetry and smooth texture, but widely available.
Condition Notes
Good to Fine condition. The shell is structurally intact with most of its original color pattern preserved, minor surface wear visible near the apex, and no major structural fractures.
Interesting Facts
Moon snails are formidable marine predators. They drill precise, bevel-edged holes into the shells of bivalves using an acidic secretion and their radula, then feed on the soft tissue inside. They also create distinct sand collars to house their eggs.
Ecological Role
Acts as an apex carnivorous predator among benthic micro-invertebrates, helping control bivalve populations. Their empty shells often serve as vital secondary housing for hermit crabs.
Similar Species
Neverita lewisii (Lewis's Moon Snail), which is significantly larger and found on the Pacific coast, and Euspira heros (Northern Moon Snail), which has a higher, more prominent spire.
Beach Finding Tips
Look along sandy beaches at low tide, particularly near sandbars or after a strong storm. Keep an eye out for their famous 'sand collars' (round, sandy egg masses) or small round holes in bivalve shells indicating moon snail predation nearby.