West Indian Keyhole Limpet (also known as the Barbados Keyhole Limpet)
Phylum: Mollusca, Class: Gastropoda, Order: Vetigastropoda, Family: Fissurellidae, Genus: Fissurella, Species: Fissurella barbadensis · Fissurellidae (Keyhole limpet family) · Gastropod (univalve); whole shell; low-conical or cap-shaped
Species
Fissurella barbadensis
Shell Type
Gastropod (univalve); whole shell; low-conical or cap-shaped
Family
Fissurellidae (Keyhole limpet family)
Size
Approximately 1 to 1.5 inches in length. This is typical for the species, with most mature adults ranging between 0.8 and 1.5 inches.
Color & Pattern
Featuring strong contrasting concentric bands of dark gray-black and white. The exterior shows a heavily sculptured, checkered pattern with radial ribs crossed by growth lines. The interior features a prominent central oval aperture (the keyhole) with a greenish-white or translucent nacreous border.
Rarity
Common, frequently found by beachcombers exploring rocky shorelines and tide pools within its range.
Habitat
Intertidal and shallow subtidal zones, typically found firmly attached to rocky substrates, limestone benches, and wave-swept intertidal rocks where they graze on algae. Marine species.
Geographic Range
Western Atlantic Ocean, ranging from the Florida Keys and the Caribbean through the Gulf of Mexico down to Brazil, as well as parts of Bermuda.
Description
A stunning cap-shaped univalve characterized by its distinctive oval apical opening or 'keyhole' near the apex. The exterior exhibits prominent radiating ribs intersected by concentric growth rings, creating a robust, lattice-like texture. The high-contrast black-and-white banded coloration makes it visually striking, while the smooth interior aperture serves as an exhalant water outlet for the living animal.
Key Features
The presence of the central apical perforation (keyhole), a strongly toothed or crenulated margin, and the bold, high-contrast black-and-white checkered radial ribbing.
Collector Value
Commonly collected by beachcombers and beginner shell enthusiasts. While not valuable in monetary terms (usually worth only a few dollars), specimens with exceptional color contrast or large size are appreciated in decorative displays and specialized micro-mollusk or limpet collections.
Condition Notes
The shell appears to be in very good to fine condition with intact sculptural ribs, minimal wear around the margins, and a clear, well-defined keyhole aperture.
Interesting Facts
Keyhole limpets are not true limpets despite their appearance. The 'keyhole' is used to expel waste and water from the mantle cavity, a unique evolutionary feature. When threatened, they clamp down tightly onto rocks using their muscular foot, making them exceptionally difficult for predators to dislodge.
Ecological Role
As herbivorous grazers, keyhole limpets play an essential role in controlling microalgal growth on rocky shores, helping to maintain healthy benthic ecosystems. They serve as prey for various marine predators including carnivorous gastropods and shorebirds.
Similar Species
Lottia gigantea (Owl Limpet) and other Fissurella species such as Fissurella angusta. They can be distinguished by specific differences in the keyhole shape, rib density, and geographic distribution.
Beach Finding Tips
Search rocky intertidal zones, particularly around tide pools and limestone shelves during low tide. Look in shell drift accumulated in crevices or storm lines along rocky beaches.