Scotch Bonnet (or Atlantic Scotch Bonnet)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Cassidae, Genus: Semicassis, Species: S. granulata · Cassidae (Helmet and Bonnet shells) · Gastropod (snail). This is a whole shell with a globose, spiral shape.
Species
Semicassis granulata (Confidence Level: 95%)
Shell Type
Gastropod (snail). This is a whole shell with a globose, spiral shape.
Family
Cassidae (Helmet and Bonnet shells)
Size
Approximately 1.5 to 2 inches (3.8-5 cm). This appears to be a juvenile or small adult specimen; mature adults typically range from 2 to 4 inches.
Color & Pattern
Base color is a creamy white, decorated with roughly rectangular orange-brown to tan spots arranged in around five spiral rows. The patterns are somewhat diffused, suggesting natural water-wear. The apex (pointed tip) shows a slight purplish or dark hue, typical of the species.
Rarity
Common in its range, though high-quality beach specimens can be difficult to find due to their fragility.
Habitat
Marine; typically found in shallow to moderately deep water (subtidal) on sandy bottoms, often near seagrass or coral reefs.
Geographic Range
Western Atlantic, from North Carolina down through the Gulf of Mexico, Caribbean Sea, and as far south as Brazil.
Description
A beautiful decorative shell with a rounded, 'bonnet-like' shape. It features a short spire and a large body whorl. The surface is textured with fine spiral grooves and growth lines. The aperture (though not fully visible) is typically long with a thickened, 'toothed' outer lip in adults.
Key Features
Characteristic 'plaid' or square-spotted pattern; globose shape; distinctive fine spiral ridges (striae) that give it a textured feel; short spire relative to the body whorl.
Collector Value
Low to moderate. Common specimens are worth $2-$10, while larger, 'Gem' quality shells with perfect lips and dark coloration can fetch $20-$30. It is a staple of Western Atlantic collections.
Condition Notes
Good. The shell is intact with no major breaks visible. There is some minor surface erosion and sun-bleaching characteristic of a beach-found specimen. The glossiness has weathered into a matte finish. Collectibility grade: Fine.
Interesting Facts
The Scotch Bonnet is the official state shell of North Carolina (the first state to designate one). These snails are predators that specialized in eating sea urchins and sand dollars. The common name comes from its resemblance to a traditional Scottish woolen cap (Tamo' Shanter).
Ecological Role
Active carnivore; helps control populations of echinoderms (sea urchins). They use specialized enzymes and a radula to drill into the hard tests of their prey. Conservation status is generally stable.
Similar Species
Semicassis cicatricosa is very similar but usually smoother with less defined ridges. Phalium glaucum (Grey Bonnet) is larger and lacks the distinct orange squares.
Beach Finding Tips
Look on sandy Atlantic beaches after a storm or strong high tide. They are often found in the 'wash line' mixed with seaweed and debris. North Carolina's Outer Banks are famous for these.