Fissurella costata

Fissurella costata, commonly known as the “Costate Keyhole Limpet,” is a marine gastropod mollusk belonging to the family Fissurellidae.

Description and Characteristics

Fissurella costata is a relatively small limpet species, typically reaching a maximum size of around 3.5 centimeters. The shell of Fissurella costata is characterized by its distinctive, elongated oval shape and its prominent, radial ribs that extend from the apex to the margin. The shell’s exterior is typically a grayish-brown color, often with a darker, reddish-brown hue along the ribs. A key feature of this species is the presence of a small, circular “keyhole” opening near the apex of the shell, which allows for the expulsion of waste products. The interior of the shell is usually pearly white with a smooth, glossy surface.

Habitat and Occurrence

Fissurella costata is a common species found in the intertidal and subtidal zones of the rocky shores of the northeastern Pacific Ocean. This species is particularly abundant along the coastlines of California, Oregon, and Washington, where it occupies a variety of habitats, including tide pools, rocky reefs, and kelp forests. Fissurella costata typically thrives in areas with moderate wave exposure and abundant algae growth. This species is often found clinging to rocks, boulders, and other hard substrates, where it can readily access its food source.

Taxonomy

Fissurella costata is classified within the phylum Mollusca, belonging to the Class Gastropoda, Order Lepetellida, and Family Fissurellidae. This taxonomic placement reflects the unique characteristics of this species, including its external shell morphology, feeding habits, and its adaptation to life in the intertidal zone.

Feeding

Fissurella costata is an herbivorous species, feeding primarily on algae and other microscopic organisms that grow on the surfaces of rocks and other hard substrates. This species utilizes a specialized feeding apparatus known as a radula, which is a ribbon-like structure covered in rows of tiny, chitinous teeth. The radula allows Fissurella costata to scrape off algae and other food particles from the substrate, effectively grazing on the available food source.