Shark Eye Moon Snail (also known as Northern Moon Snail or Atlantic Moon Snail)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Euspira, Species: Euspira heros · Naticidae (Moon Snail family) · Gastropod (univalve) with a globose, spiral shape; whole shell
Species
Euspira heros
Shell Type
Gastropod (univalve) with a globose, spiral shape; whole shell
Family
Naticidae (Moon Snail family)
Size
Approximately 2 to 3 inches in diameter, which is medium to large for the species. Adults typically range from 2 to 4.5 inches.
Color & Pattern
Muted gray, brownish-gray, and weathered white tones with subtle fine growth lines. The colors are heavily sun-bleached and worn due to environmental exposure, characteristic of a beach-worn specimen. The interior shows a dark, cavernous aperture with a deeply recessed umbilicus.
Rarity
Common, frequently found washed up on sandy beaches within its native range.
Habitat
Found primarily in shallow subtidal to intertidal marine waters, living buried beneath sand or mud flats where it hunts for bivalve prey.
Geographic Range
Western Atlantic Ocean, from the Gulf of St. Lawrence and Nova Scotia down to North Carolina.
Description
A sturdy, globular gastropod shell featuring a smooth yet weathered exterior marked by concentric growth lines. It has a low spire, a rounded body whorl, and a characteristic deep, open umbilicus leading into the central axis. The aperture is large, semi-lunate, and lacks any operculum in this specimen.
Key Features
Globular or spherical shape, low spire, smooth to finely striated surface, large aperture, and a distinctive deep, open umbilicus (navel) at the base.
Collector Value
Low to moderate value. While very popular for casual beachcombers and shellcraft, heavily weathered specimens like this hold little monetary value for advanced conchological collectors, who seek pristine, glossy specimens with intact operculums.
Condition Notes
Fair condition; beach-worn with significant surface weathering, loss of original glossy or brownish periostracum, and complete bleaching of the natural color. No major fractures or holes, but heavily eroded.
Interesting Facts
Moon snails are famous predatory gastropods that drill perfectly bevelled circular holes into the shells of clams using a combination of acidic secretions and their radula to feed on the soft tissue inside.
Ecological Role
Acts as an important apex predator and bioturbator in soft-bottom marine benthic communities by controlling bivalve populations and providing vacant shells for hermit crabs.
Similar Species
Neverita duplicata (Shark Eye / Lined Moon Snail), which typically features a callus that partially or fully fills the umbilicus, unlike the widely open umbilicus of Euspira heros.
Beach Finding Tips
Look along sandy ocean-facing beaches, especially at low tide or after storm surges. Keep an eye out for 'moon snail collars' (sand collars), which are the egg masses left behind by these snails.