American Star Shell, also known as the Long-spined Star Shell
Phylum: Mollusca, Class: Gastropoda, Order: Vetigastropoda, Family: Turbinidae, Genus: Lithopoma, Species: Lithopoma americanum · Turbinidae (Turban and Star Shell family) · Gastropod (snail/univalve), whole shell, spiral shape with prominent peripheral spines
Species
Lithopoma americanum
Shell Type
Gastropod (snail/univalve), whole shell, spiral shape with prominent peripheral spines
Family
Turbinidae (Turban and Star Shell family)
Size
Approximately 1.5 to 2 inches in diameter, which is typical for an adult of this species. Species ranges generally from 1 to 2.5 inches.
Color & Pattern
Pale off-white to pearly cream base color with subtle hints of greenish-gray or pinkish iridescence. The surface shows nacreous highlights, particularly where worn or around the spire, indicating a strong mother-of-pearl layer beneath the outer calcitic layer. Colors appear slightly weathered and sun-bleached from wave action.
Rarity
Common to Uncommon, frequently found by snorkelers and occasionally washed up on beaches after storms.
Habitat
Found in shallow subtidal waters, often dwelling on rocky reefs, coral rubble, and hard seagrass bottoms from the low intertidal zone down to depths of about 30 meters.
Geographic Range
Western Atlantic Ocean, including Southeast Florida, the Florida Keys, the Bahamas, the Caribbean Sea, and parts of the Gulf of Mexico.
Description
A compact, heavy-bodied marine snail shell featuring a depressed conical or top-like shape. The periphery is adorned with a prominent series of flattened, triangular, spine-like projections radiating outward. The spire is low with rounded whorls covered in fine granular cords and spiral ridges. The interior of the aperture is silvery and nacreous.
Key Features
Distinguished by its depressed star-like shape, the row of flattened spines along the periphery of the body whorl, granular sculptural cords on the dorsal surface, and a nacreous aperture.
Collector Value
Modest collector value, typically ranging from $2 to $10 depending on size, intactness of spines, and color preservation. It is a popular species for casual shell collectors and educational displays.
Condition Notes
Good condition. The shell is structurally intact with some wear and bluntness on the peripheral spines due to wave tumble. Coloration is somewhat bleached from sun exposure, showing prominent nacre. Collectibility grade is Good.
Interesting Facts
Like other members of the Turbinidae family, Lithopoma species possess a thick, calcareous operculum (trapdoor) that seals the aperture when the animal withdraws into its shell. This heavy operculum is sometimes polished and used in jewelry, commonly known as 'cat's eye' stones.
Ecological Role
As herbivorous grazers, these snails play an important role in controlling algae populations on reefs and hard substrates. They serve as prey for various carnivorous gastropods, crustaceans, and fish.
Similar Species
Lithopoma caelatum (Cavitary Star Shell), which has more upright, blunter nodes and different sculptural cords, and Lithopoma tuber (Green Star Shell), which lacks the prominent peripheral spines and is typically larger and greener.
Beach Finding Tips
Best found by beachcombing after heavy storms or rough seas in the Florida Keys and the Caribbean. Snorkeling in shallow rocky areas and coral rubble fields at low tide yields the best specimens.