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 with a globose, spiral shape.
Species
Neverita duplicata
Shell Type
Gastropod (univalve); whole shell with a globose, spiral shape.
Family
Naticidae (Moon Snail family)
Size
Approximately 1 to 1.5 inches in diameter. This is a sub-adult specimen; adults typically range from 2 to 5 inches.
Color & Pattern
Base color is a slate gray to brownish-tan with subtle growth lines. The apical area (center) shows an eye-like pattern with a light center surrounded by a darker ring. The interior is typically a glossy mahogany or chocolate brown.
Rarity
Very Common; frequently found washed up on North Carolina beaches like Holden Beach.
Habitat
Shallow water marine environments, typically found in intertidal and subtidal sandy bottoms or mudflats where it can burrow.
Geographic Range
Western Atlantic coast from Massachusetts to the Gulf of Mexico and the Caribbean.
Description
A smooth, globose, and somewhat flattened shell. It features a very low spire and a large, wide body whorl. The surface is mostly smooth with very fine growth lines. Its most striking feature is the large, flat callus that partially or completely covers the umbilicus (the 'belly button' hole).
Key Features
The most diagnostic feature is the large, dark brownish-purple or gray callus that covers the umbilicus, which distinguishes it from other moon snails. The 'eye' pattern on the top of the spire is also characteristic.
Collector Value
Low monetary value due to its commonality, but high educational value. It is a staple of North Carolina beachcombing. Larger specimens with intact glossy interiors are preferred.
Condition Notes
Fair to Good. The shell shows some minor beach-worn erosion on the apex and edges. The natural color is somewhat muted by sun-bleaching, and there is no visible periostracum.
Interesting Facts
This snail is a predatory carnivore that uses its radula (a tongue-like organ) to drill perfectly circular holes into the shells of clams and other mollusks. They also produce unique egg cases known as 'sand collars' which are made of sand and mucus.
Ecological Role
High-level predator in the sandy-bottom ecosystem; helps control the population of bivalves. They are also common prey for sea stars and larger crabs.
Similar Species
Euspira heros (Northern Moon Snail), which lacks the large umbilical callus and typically has a more open umbilicus.
Beach Finding Tips
Look in the wrack line or at the low-tide mark after a storm. They are often found half-buried in wet sand as the tide recedes.
Notes
Holden Beach, NC