Red-Spotted Keyhole Limpet
Phylum: Mollusca, Class: Gastropoda, Order: Vetigastropoda, Family: Fissurellidae, Genus: Fissurella, Species: Fissurella rubropicta · Fissurellidae (Keyhole limpet family) · Gastropod univalve with an oval cap-shaped morphology and a distinctive apical aperture (keyhole)
Species
Fissurella rubropicta
Shell Type
Gastropod univalve with an oval cap-shaped morphology and a distinctive apical aperture (keyhole)
Family
Fissurellidae (Keyhole limpet family)
Size
Approximately 1 to 1.5 inches in length, which is typical for an adult of this species, with species sizes generally ranging from 0.75 to 2 inches.
Color & Pattern
Whitish to cream base color featuring radial ribs with prominent, distinct bright red or crimson spots and patches, most notably a vibrant red blotch near the margin and a reddish ring surrounding the keyhole aperture.
Rarity
Uncommon, as finding a specimen with such intact, vibrant red markings requires dedicated searching in rocky intertidal habitats.
Habitat
Intertidal to shallow subtidal zones, typically found firmly attached to rocky substrates, boulders, and tide pools where wave action is moderate to high.
Geographic Range
Eastern Pacific Ocean, ranging from southern California down along the coast of Baja California, Mexico.
Description
An attractive and robust keyhole limpet featuring a low, conical cap-shaped shell adorned with fine, closely spaced radial ribs. The apex is perforated by a central or slightly anterior oblong aperture resembling a keyhole, which is characteristic of the genus. The margin is scalloped, and the exterior exhibits striking crimson spots over a pale background.
Key Features
The presence of a central apical opening (keyhole) combined with strong radial ribbing and distinct, bright red spots or patches on a whitish background distinguishes this species from other limpets.
Collector Value
Moderately desirable among marine shell collectors, particularly for those focusing on West American micromollusks and limpets. Specimens with exceptionally bright and vivid red coloration command higher interest.
Condition Notes
The specimen appears to be in very good, intact condition with the original bright red coloration well-preserved, little to no significant erosion, and a clean aperture rim, grading as a Fine to Gem collector specimen.
Interesting Facts
The keyhole at the top of the shell is not just for show; it serves as an exit for water after it passes over the gills and for waste elimination, allowing the animal to maintain a low, secure profile against rocks without needing to lift its shell.
Ecological Role
Keyhole limpets act as important herbivores in rocky intertidal ecosystems, grazing on microalgae and encrusting films to help maintain the balance of algal communities on rocks. They serve as prey for various marine predators including sea stars and specialized fish.
Similar Species
Fissurella volcano (Volcano Keyhole Limpet), which is generally smaller and features reddish or pinkish rays rather than distinct bold red spots, and Megathura crenulata (Giant Keyhole Limpet), which is much larger with a vastly different mantle-to-shell proportion.
Beach Finding Tips
Look along rocky shores, jetties, and tide pools during extreme low tides. Inspect the underside of boulders and rocks where limpets cling tightly, though empty shells may occasionally wash up among shell drift in rocky coves.