Keyhole Limpet
Phylum: Mollusca, Class: Gastropoda, Order: Lepetellida, Family: Fissurellidae, Genus: Fissurella, Species: Fissurella barbadensis · Fissurellidae (Keyhole Limpet family) · Gastropod, whole shell, cap-shaped with an apical opening
Species
Fissurella barbadensis
Shell Type
Gastropod, whole shell, cap-shaped with an apical opening
Family
Fissurellidae (Keyhole Limpet family)
Size
Approximately 1 inch in length, which is average for this species. Adults typically range from 0.75 to 1.5 inches.
Color & Pattern
Purplish-brown and white radiating stripes and check patterns on a cream-to-pinkish base. The colors appear natural and well-preserved. The interior is glossy white with a smooth margin around the keyhole opening.
Rarity
Common
Habitat
Found in the intertidal and shallow subtidal zones, typically clinging firmly to hard rocky substrates, limestone benches, and coral rubble in high-energy surf environments.
Geographic Range
Western Atlantic Ocean, including the Caribbean Sea, the Gulf of Mexico, southern Florida, Bermuda, and down to the coast of Brazil.
Description
A charming and compact cap-shaped shell featuring fine radial ribs and concentric growth lines that create a textured, lattice-like exterior. The hallmark feature is the small, oval-to-keyhole-shaped opening (trema) located near the apex, which serves as an exit for water after passing over the gills. The margin is scalloped to match the external ribs.
Key Features
Distinguished by the apical keyhole opening and the distinct pinkish-brown and white checkered or striped radial pattern, which separates it from other keyhole limpet species.
Collector Value
Inexpensive and widely available, typically worth a few dollars, but highly popular among beginning beachcombers and shell enthusiasts due to its unique geometry and pretty coloration.
Condition Notes
Fine to Gem condition. The shell is fully intact, retains vibrant natural coloration with minimal fading, and shows sharp radial ribbing without major wear or boring marks.
Interesting Facts
The keyhole opening at the top of the shell is not just for respiration; it also allows the limpet to expel waste cleanly away from its head and gills. Unlike typical snails that retreat into a coiled shell, limpets clamp down tightly onto rocks using a powerful muscular foot to withstand pounding waves.
Ecological Role
Acts as an important marine herbivore, scraping microscopic algae off rocks, which helps maintain the balance of the rocky intertidal ecosystem. It serves as prey for various predatory snails, fish, and shorebirds.
Similar Species
Diodora listeri (Lister's Keyhole Limpet), which has a more centrally located and pronounced keyhole with a more strongly pitted surface texture.
Beach Finding Tips
Look along rocky shores, jetties, and limestone formations at extremely low tide. Search among tide pools and turn over loose rocks or examine crevices where they cling tightly.