Shark Eye, Northern Moon Snail, Atlantic Moon Snail
Phylum: Mollusca, Class: Gastropoda, Subclass: Caenogastropoda, Order: Littorinimorpha, Superfamily: Naticoidea, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon Snail family) · Gastropod (univalve snail), complete shell with missing operculum. Shape is subglobose to depressively round with a flattened spire.
Species
Neverita duplicata (formerly Polinices duplicatus)
Shell Type
Gastropod (univalve snail), complete shell with missing operculum. Shape is subglobose to depressively round with a flattened spire.
Family
Naticidae (Moon Snail family)
Size
Approximately 2 to 2.5 inches (5 to 6.5 cm) in width. Typical adult size ranges from 1.5 to 3.5 inches (4 to 9 cm).
Color & Pattern
Pale greyish-tan to light brownish-cream exterior with subtle peach or flesh-colored undertones, indicating sun-bleaching. Interior aperture displays a smooth, polished light peach/beige hue. The prominent umbilical callus feature exhibits a dark chestnut-brown tint.
Rarity
Common; frequently washed ashore on sandy Atlantic and Gulf coast beaches, though large, undamaged specimens are always a prized beachcombing find.
Habitat
Sublittoral and intertidal zones, preferring soft substrates such as shallow sandy bottoms, sandbars, and muddy sand flats in marine environments.
Geographic Range
Western Atlantic Coast of North America, extending from Cape Cod, Massachusetts down to Florida, through the Gulf of Mexico to Mexico.
Description
A smooth, rounded gastropod shell featuring a depressed spire and a large, inflated body whorl. The shell's dominant feature is its wide, semi-lunar aperture and a deep umbilical pit almost completely covered by a thick, smooth, dark chestnut-brown callus deposit. The exterior surface shows fine, concentric growth lines.
Key Features
Flattened dome-like spire; wide, rounded body whorl; large, smooth, purple-brown to dark chestnut umbilical callus that nearly bridges over a deep umbilical cavity; smooth exterior with fine growth lines.
Collector Value
Low monetary value (typically $1 to $5 for beach specimens), but high educational and aesthetic appeal for regional Atlantic coast shell collections due to its distinctive predatory anatomy and classic moon snail profile.
Condition Notes
Fair to Good condition. Showings moderate beach wear and sun-bleaching with slight chalkiness on the outer spire. Lip of the outer aperture is slightly worn but mostly intact. The critical diagnostic feature—the umbilical callus deposit—is well preserved.
Interesting Facts
Moon snails are voracious predatory snails that use their specialized radula to drill clean, countersunk circular holes through the shells of clams and other bivalves before secreting digestive enzymes to consume the prey inside. Their eggs are laid in distinctive collar-shaped rings made of sand and mucus, often found on beaches and known as 'sand collars'.
Ecological Role
Key benthic predator regulating populations of hard clams, surf clams, and other bivalves. Serves as a food source for sea stars, shorebirds, and crabs, while empty shells frequently become homes for large hermit crabs.
Similar Species
Euspira heros (Northern Moon Snail) - distinguished by having an open, deep umbilicus without a thick covering callus; Glossaulax reclusiana (Southern Moon Snail) - features a distinct groove dividing the umbilical callus.
Beach Finding Tips
Look along low tide lines, sandbars, and tidal flats after strong offshore storms or exceptionally low tides. Frequently found half-buried in soft damp sand near shallow water channels.