Atlantic Oyster Drill
Phylum: Mollusca, Class: Gastropoda, Order: Neogastropoda, Family: Muricidae, Genus: Urosalpinx, Species: Urosalpinx cinerea · Muricidae (Murex or Rock Snail family) · Gastropod (snail); spiral shape with a high spire and distinct siphonal canal.
Species
Urosalpinx cinerea
Shell Type
Gastropod (snail); spiral shape with a high spire and distinct siphonal canal.
Family
Muricidae (Murex or Rock Snail family)
Size
Approximately 0.75 - 1 inch (19-25mm). This is a typical adult size; the species rarely exceeds 1.5 inches.
Color & Pattern
Mottled grayish-brown to tan with hints of dull yellow. The body whorl shows subtle vertical ribs and spiral cords. The interior aperture typically lacks bright colors, appearing pale gray or white.
Rarity
Very Common; frequently found on beaches near oyster beds or inlets like those at Holden Beach.
Habitat
Intertidal and shallow subtidal zones. Prefers hard substrates, especially oyster reefs and rocky jetties in marine and brackish estuarine environments.
Geographic Range
Common along the Western Atlantic coast from Nova Scotia to Florida. It was also introduced to the West Coast of the US and parts of Europe.
Description
A rugged, fusiform shell with a pointed spire. The surface is sculpted with roughly 9-12 rounded longitudinal ribs crossed by fine spiral threads. The aperture is oval with a short, straight siphonal canal. Its thick walls are built for protection in turbulent coastal waters.
Key Features
Distinguished by its 'drilling' morphology: a rough texture, relatively high spire, and thick outer lip. Unlike many larger muricids, it lacks long spines, appearing more compact and utilitarian.
Collector Value
Minimal monetary value ($1-$3) due to its abundance, but highly valued for educational collections as a classic example of an estuarine predator.
Condition Notes
The specimen shows light beach wear (rounding of the ribs) and moderate fading. The tip of the spire remains mostly intact. Overall condition: Good/Fair (standard beach-found quality).
Interesting Facts
This snail is a specialized predator. It uses its radula and an acid-secreting gland to drill a perfectly circular hole through the shells of oysters and mussels to consume the soft tissue inside.
Ecological Role
A significant predator of bivalves. While native to the East Coast, it is considered a pest in commercial oyster fisheries due to the damage it causes to oyster spat populations.
Similar Species
Thais haemastoma (Florida Rock Snail) which is much larger with a wider aperture, and Eupleura caudata (Thick-lipped Drill) which has a more flattened shape and prominent 'wings' on the sides.
Beach Finding Tips
Look near oyster bars or along the high-tide line near inlets. At Holden Beach, check the debris piles near the 'Goldenrod' area or the Intra-Coastal Waterway side at low tide.
Notes
Holden Beach, NC