Keyhole Limpet
Phylum: Mollusca, Class: Gastropoda, Order: Vetigastropoda, Family: Fissurellidae, Genus: Fissurella, Species: Fissurella barbadensis · Fissurellidae (Keyhole limpet family) · Gastropod, whole shell, conical and cap-shaped shape
Species
Fissurella barbadensis
Shell Type
Gastropod, whole shell, conical and cap-shaped shape
Family
Fissurellidae (Keyhole limpet family)
Size
Approximately 0.75 inches (2 cm) in length, which is average for this species. Adults typically range from 0.5 to 1.5 inches.
Color & Pattern
Whitish or cream base with distinctive radial reddish-brown or purplish stripes radiating from the apex to the margin. The interior is glossy white with a green-rimmed central perforation.
Rarity
Common
Habitat
Found in the intertidal zone, clinging tightly to rocky substrates, limestone benches, and tide pools where wave action is moderate to high.
Geographic Range
Western Atlantic, including the Caribbean Sea, the Gulf of Mexico, Florida, Bermuda, and south along the coast of South America to Brazil.
Description
A small, cap-shaped marine snail shell featuring a distinct oval or keyhole-like opening at or near the apex. The exterior exhibits prominent, coarse radial ribs crossed by fine concentric growth lines, creating a checkered texture beneath striking purplish-brown and white coloration.
Key Features
The presence of a distinct apical perforation (the keyhole), radially ribbed exterior, and a scalloped margin matching the external ribs.
Collector Value
Low to moderate value. While common, they are popular among micro-shell collectors and beachcombers looking for complete specimens with vibrant color patterns.
Condition Notes
Good condition with intact margins, clear coloration, and well-defined radial ribs. Collectibility grade is Good to Fine.
Interesting Facts
The keyhole at the top of the shell serves an ecological purpose: water is drawn in under the edges of the shell for respiration and feeding, and waste is expelled directly upward through the hole.
Ecological Role
Acts as a marine herbivore, scraping microalgae off rocks using its radula, which helps maintain the balance of benthic algae in intertidal ecosystems.
Similar Species
Other keyhole limpets such as the Lobe-rayed Keyhole Limpet (Fissurella fascicularis), which can be distinguished by differences in ribbing density and internal margin characteristics.
Beach Finding Tips
Look along rocky shorelines, particularly in tide pools or among shell drift piled against rocky outcrops after storms.