Atlantic Oyster Drill
Phylum: Mollusca, Class: Gastropoda, Order: Neogastropoda, Family: Muricidae, Genus: Urosalpinx, Species: U. cinerea · Muricidae (Murex or Rock Snail family) · Gastropod (univalve); Spiral-fusiform shape. This specimen is a whole shell showing a complete spire and siphonal canal.
Species
Urosalpinx cinerea
Shell Type
Gastropod (univalve); Spiral-fusiform shape. This specimen is a whole shell showing a complete spire and siphonal canal.
Family
Muricidae (Murex or Rock Snail family)
Size
Approximately 0.75 to 1.0 inches (19-25mm). This is typical for a mature adult; they rarely exceed 1.5 inches.
Color & Pattern
Tan to reddish-brown base color. The specimen shows dark brown pigmentation on the body whorl with lighter, yellowish coloration on the outer lip. The interior (aperture) typically matches the outer color or is slightly pearly.
Rarity
Very Common. It is one of the most frequently encountered predatory snails along the mid-Atlantic coast.
Habitat
Shallow marine waters and intertidal zones. Predominantly found in oyster reefs, rocky shores, and salt marshes.
Geographic Range
Natural to the Western Atlantic coast from Canada to Florida, including the Gulf of Mexico. It is common on the North Carolina coastline near Holden Beach.
Description
A small, rugged-looking predatory snail shell. It features a moderately high, pointed spire with 5 to 6 whorls. The surface sculpture consists of prominent longitudinal ribs (approx. 9-12 on the body whorl) crossed by fine spiral cords, giving it a bumpy or reticulated texture. The aperture is oval with a short, open siphonal canal.
Key Features
Longitudinal ribs overlaid with spiral threads; oval aperture; relatively short siphonal canal compared to other Muricids; thickened outer lip that sometimes features small teeth (denticles) inside.
Collector Value
Low monetary value due to its abundance, generally $1-$5 for high-quality beach specimens. However, it is a staple in regional educational collections.
Condition Notes
Good condition. The spire is intact, though the tip shows minor wear and possible sea-bleaching. The outer lip appears slightly worn but maintains its characteristic flare. Collectibility grade: Fine.
Interesting Facts
This species is a notorious predator of oysters. It uses its radula (a sandpaper-like tongue) and a specialized boring organ to drill a perfectly circular hole through the oyster's shell to consume the meat inside. Because of this, it is considered a significant pest by the commercial oyster industry.
Ecological Role
A key secondary consumer in reef ecosystems. They regulate bivalve populations but can cause ecological shifts if they overpopulate oyster restoration sites. They are preyed upon by crabs and larger predatory snails.
Similar Species
Eupleura caudata (Thick-lipped Drill), which has two prominent lateral varices (fins) and a more compressed shape; and young Stramonita haemastoma (Florida Rock Snail), which is much larger and thicker as an adult.
Beach Finding Tips
Look for these near oyster bars or among clumped oyster shells at low tide. In Holden Beach, check the wrack line or near the intercoastal waterway side where oyster reefs are concentrated.
Notes
Holden Beach, NC