Shark Eye, Atlantic Moon Snail
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon Snail family) · Gastropod (Univalve); spiral/globular fragment (spire only)
Species
Neverita duplicata
Shell Type
Gastropod (Univalve); spiral/globular fragment (spire only)
Family
Naticidae (Moon Snail family)
Size
Approximately 1.5 to 2 inches in diameter. This represents the spire of a medium-sized adult; complete specimens typically reach 3-5 inches.
Color & Pattern
Base color of cream and tan with a distinctive lead-gray to brownish-blue hue on the older whorls. The apex (center) shows a slight orange-brown tint. The surface has a smooth, slightly polished appearance despite beach wear.
Rarity
Very Common. These are among the most frequently found predatory snail remnants on South Carolina beaches.
Habitat
Shallow subtidal zones and intertidal sand flats. They prefer sandy substrates where they can burrow just beneath the surface to hunt for prey.
Geographic Range
Western Atlantic coast from Massachusetts to Florida, and throughout the Gulf of Mexico. Extremely common in the Carolinas.
Description
This specimen is the spire fragment of a Moon Snail. It features a low, rounded profile with a smooth texture and a distinctively 'swirled' look resembling an eye. The shell is thick-walled and heavy for its size, characterized by a large body whorl (mostly missing here) and a deep, umbilical callus that typically covers the center hole in complete specimens.
Key Features
The most diagnostic feature is the lead-gray coloration paired with the flattened, clockwise spiral. In a complete specimen, the large, dark brown, button-like callus covering the umbilicus is the primary identifier for Neverita duplicata.
Collector Value
Minimal. While the species is iconic, this specific specimen is a broken fragment. Intact, large 'Gem' quality specimens with a shiny periostracum can hold modest value ($2-$10), but beach-worn fragments are generally considered 'study pieces' or craft material.
Condition Notes
Poor to Fair. This is a beach-worn fragment consisting only of the upper whorls (the spire). The large body whorl and aperture have been broken away by surf action. The color is slightly dull due to sand abrasion, though the structural integrity of the spire remains solid.
Interesting Facts
Moon snails are voracious predators that hunt clams. They use a specialized tongue-like organ called a radula to drill a perfectly circular hole into the shell of their prey. They also create 'sand collars'—unique, rubbery egg cases made of sand and mucus that look like a discarded plunger head.
Ecological Role
Important apex invertebrate predators in the sandy benthic community. They control populations of bivalves like quahogs and surf clams. They are not currently protected or endangered in South Carolina.
Similar Species
Euspira heros (Northern Moon Snail), which is larger and lacks the large purple-brown callus covering the umbilicus; and Polinices lacteus (Milk Moon Snail), which is smaller and pure white.
Beach Finding Tips
Best found at Myrtle Beach after a storm or during low tide on flat sandy stretches. Look for the 'eye' pattern peeking out of the sand or in shell piles near the high-tide line.
Notes
Myrtle Beach in SC, broken shell