Shark Eye Moon Snail (also known as Northern Moon Snail or Atlantic Moon Snail)
Kingdom: Animalia, Phylum: Mollusca, Class: Gastropoda, Subclass: Caenogastropoda, Order: Littorinimorpha, Superfamily: Naticoidea, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon Snail family) · Gastropod (univalve snail). Single complete shell, globe-like to low-spired spiral shape.
Species
Neverita duplicata (formerly Polinices duplicatus)
Shell Type
Gastropod (univalve snail). Single complete shell, globe-like to low-spired spiral shape.
Family
Naticidae (Moon Snail family)
Size
Approximately 2.5 to 3 inches (6-7.5 cm) in diameter. Adult specimens typically range from 1.5 to 3.5 inches (4-9 cm) across, making this an average to large-sized specimen.
Color & Pattern
Exterior features soft shades of grey, tan, buff, and subtle lavender-brown tones following concentric growth lines. The apical whorls show a slightly darker bluish-grey tint, giving it the characteristic 'eye' appearance. The shell surface has a smooth, matte finish due to slight natural beach weathering.
Rarity
Common (frequently found washed ashore on sandy beaches along the US Atlantic coast and Gulf Coast).
Habitat
Sublittoral and intertidal zones, preferring soft substrates such as sand, muddy sand, and shallow sandbars. Marine species inhabiting shallow coastal waters down to depths of about 150 feet.
Geographic Range
Western Atlantic Coast, ranging from Massachusetts south to Florida, the Gulf of Mexico, and into the Caribbean.
Description
A smooth, rounded, sub-globular gastropod shell featuring a low, depressed spire and a large, inflated body whorl. The surface is marked by fine, delicate concentric growth lines. Viewed from above, the spiraling whorls taper to a central apex resembling a dark eye pupil.
Key Features
Low depressed spire with a wide body whorl; smooth polished surface without axial ribs or heavy spines; a prominent lobe-like brown or grey callus that partially covers a deep umbilical opening on the ventral side.
Collector Value
Modest collector value ($2 - $10) due to its abundance, though large, fully glossy specimens with deep coloration or preserved operculums are favored in display collections.
Condition Notes
Good condition. Shows slight surface wear and minor fading from sun exposure and wave action, but retains structural integrity with intact apex and smooth margins. Collectibility Grade: Good / Fine.
Interesting Facts
Moon snails are predatory marine snails that hunt clams by drilling precise counter-sunk circular holes into their shells using a specialized radula and chemical secretions. They lay unique collar-shaped egg masses made of sand grains cemented together with mucus, commonly called 'sand collars'.
Ecological Role
Key benthic predator regulating populations of bivalves like quahogs, hard clams, and surf clams. Forms a staple component of the coastal soft-sediment food web, and its empty shells provide critical shelter for hermit crabs.
Similar Species
Euspira heros (Northern Moon Snail, which lacks the prominent umbilical callus), Sinum perspectivum (White Baby Ear, which is much flatter), and Naticarius canrena (Coloured Moon Snail, which exhibits distinct brown checkered bands).
Beach Finding Tips
Look along low-tide sandy beaches, barrier island mudflats, and near shallow sandbars after strong offshore storms or exceptionally low spring tides.