Screw Shell or Turret Shell
Phylum: Mollusca, Class: Gastropoda, Order: Caenogastropoda, Family: Turritellidae, Genus: Turritella, Species: Turritella terebra · Turritellidae (Turret shell family) · Gastropod, whole shell, elongate spiral shape
Species
Turritella terebra
Shell Type
Gastropod, whole shell, elongate spiral shape
Family
Turritellidae (Turret shell family)
Size
Approximately 2 to 3 inches in length, which is average for this species. Adults typically range from 2 to 5 inches.
Color & Pattern
Uniform chalky white, likely sun-bleached with original brown or yellowish coloration faded. The exterior features prominent spiral ridges, and the interior of the small, rounded aperture matches the exterior white.
Rarity
Common
Habitat
Found in marine environments, specifically in shallow subtidal zones down to moderate depths, burrowing in sandy or muddy substrates.
Geographic Range
Indo-West Pacific region, ranging from East Africa and the Red Sea through Southeast Asia to Australia and Japan.
Description
An elegant, highly elongated spiral shell tapering to a sharp apex. It features numerous tightly coiled whorls ornamented with strong, distinct spiral cords and ridges. The aperture is small and rounded, characteristic of turret shells.
Key Features
Extremely high-spired, turreted shape with numerous whorls and pronounced spiral ribs, lacking the wide body whorl typical of many other gastropods.
Collector Value
Low to moderate value. While very popular among beginner collectors for their geometric beauty, common species like this are inexpensive and widely available in shell shops.
Condition Notes
Good condition, mostly intact with a slightly worn apex. The shell is thoroughly sun-bleached to pure white, typical of beach-worn specimens. Grade: Good.
Interesting Facts
Turritella snails are ciliary feeders, using their gills to filter microscopic organic particles and phytoplankton from the water column. The family name derives from the Latin 'turritus', meaning turreted.
Ecological Role
Turritellas play an important role in benthic food webs as microphagous filter feeders and serve as prey for various carnivorous gastropods, fish, and crustaceans.
Similar Species
Other members of the Turritellidae family and Terebridae (Auger shells). Augers generally have a smoother surface and a distinct notch at the base of the aperture.
Beach Finding Tips
Look along sandy beaches following storms or rough wave action, particularly near offshore sandbars or mudflats where these snails live in colonies.