Scotch Bonnet (Alternate names: Star Shell, Bonnet Snail)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Cassidae, Genus: Semicassis, Species: Semicassis granulata · Cassidae (Helmet and Bonnet family) · Gastropod (snail/univalve), whole shell, spiral shape
Species
Semicassis granulata
Shell Type
Gastropod (snail/univalve), whole shell, spiral shape
Family
Cassidae (Helmet and Bonnet family)
Size
Approximately 1.5 to 2 inches, which is on the smaller side for this species. Adults typically range from 2 to 4 inches in length.
Color & Pattern
Creamy white or pale yellow base color decorated with distinctive rows of square or rectangular brownish-orange spots and bands. The colors appear mostly natural with slight sun-bleaching. The surface has a granulated or beaded texture.
Rarity
Common to Uncommon. While highly desired and a treasured find for beachcombers along the North Carolina coast, dedicated searching after storms usually yields specimens.
Habitat
Found in shallow subtidal waters down to moderate depths, inhabiting sandy bottoms, offshore sand bars, and areas near seagrass beds or rocky outcrops in marine environments.
Geographic Range
Western Atlantic Ocean from North Carolina down through the Gulf of Mexico, the Caribbean, and south to Brazil.
Description
A classic, solid, oval-shaped bonnet shell featuring distinct spiral ridges intersected by fine vertical grooves, creating a beaded or granulated exterior texture. It possesses a short spire, a well-developed outer lip that is slightly thickened and toothed on the inner edge, and a shallow anterior canal.
Key Features
Distinctive rounded, dome-like body whorl with strong spiral cords, finely beaded or granulated sculptural texture, and rows of characteristic square brown spots arranged in spiral bands.
Collector Value
Moderately high collectibility, primarily driven by regional sentiment and cultural significance as a state shell. Common specimens hold minor monetary value, but large, pristine, gem-grade specimens with vibrant color patterns are prized by regional collectors.
Condition Notes
Good condition overall, largely intact with distinct spiral cords and visible coloration, though showing mild signs of beach wear, minor tip erosion, and slight sun-fading. Collectibility grade is Good.
Interesting Facts
The Scotch Bonnet was officially designated as the State Shell of North Carolina in 1965. Living bonnet snails are specialized predators that feed almost exclusively on sea urchins and sand dollars, using their acidic secretions and radula to bore into or pry open their prey.
Ecological Role
Acts as an important carnivorous predator controlling sea urchin and benthic invertebrate populations. Empty shells frequently serve as crucial mobile homes for hermit crabs. The species is not currently endangered, but localized populations are impacted by heavy beach shell collection.
Similar Species
Can be confused with other helmet or tun shells, such as the Reticulate Helmet (Cypraecassis testiculus), but differs by its more rounded bonnet shape, granulated cords, and distinct brown spot banding.
Beach Finding Tips
Best found on North Carolina outer banks beaches immediately following heavy offshore storms, rough surf, or dredging operations. Look along shell lines deposited at extreme low tide.
Notes
NC beaches