Fissurella nigra, commonly known as the black keyhole limpet, is a species of marine gastropod mollusk belonging to the family Fissurellidae. This species exhibits distinctive characteristics and plays a crucial role in its specific marine environment.
Description & Characteristics
Fissurella nigra is characterized by its dark, often black, shell, which is typically 2-4 cm in length. The shell is conical and possesses a distinct, circular opening at the apex, resembling a keyhole, giving rise to its common name. This opening, known as the “anal fissure,” serves as an exit for water and waste products. The shell’s surface is typically smooth or slightly textured, and its coloration can range from dark brown to black, with some individuals displaying faint patterns or markings.
Habitat and Occurrence
Fissurella nigra primarily inhabits rocky intertidal zones and subtidal areas along the coasts of the eastern Pacific Ocean. This species is commonly found in the intertidal zone, where it is exposed to the air during low tide and submerged during high tide. Its distribution extends from California in the United States to Baja California in Mexico. Within these regions, Fissurella nigra is particularly prevalent in areas with rocky substrates, such as reefs and rocky shores. This species is generally found in the infralittoral zone, which is characterized by its proximity to the shoreline and exposure to wave action.
Taxonomy
Fissurella nigra is classified as a member of the Class: Gastropoda, Order: Lepetellida, and Family: Fissurellidae. This taxonomic classification highlights its relationships with other marine snails and its unique adaptations as a member of the keyhole limpet family.
Feeding
Fissurella nigra is an herbivorous species, feeding primarily on algae that grow on rocks and other surfaces in its habitat. Its diet consists mainly of diatoms, a type of microscopic algae, as well as larger seaweeds. It utilizes its radula, a tongue-like structure with rows of teeth, to scrape algae off the substrate. Fissurella nigra‘s feeding behavior is essential to the health of its ecosystem, as it helps to control the growth of algae and maintain a balance within the marine community.
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