Keyhole Limpet Shells of the Fissurellidae Family
Eight Keyhole Limpets of the Fissurellidae Family can be found in this website:
Stromboli Keyhole Limpet Shell
Phylogeny: Keyhole Limpets of the Fissurellidae Family are gastropod mollusks in the order Lepetellida. Shells of this order are found in marine environments and are characterized by their specialize foot that is used for clinging to hard substrates. The superfamily Fisssurelloidea is one of five superfamilies in this order. Fissurellidae is the only family within this superfamily. This large family is divided into five subfamilies – Emarginulinae, Fissurellideinae, Fissurellinae, Rimulinae, and Zeidorinae. There are forty-six genera in this family and more than five hundred species. Shells in this family are also commonly known as Slit Limpets and Volcano Limpets
Description: Keyhole Limpets are conical or plate-like in profile and ovate in outline. They are small to large in size. Each shell has either an oval hole located at the summit, a slit-like hole located just anterior of the apex, or a slit at the anterior end of the shells margin. The hole or slit provides respiration and waste elimination. Shell sculpture consists primarily of radial ribbing or commarginal ridges. The interior is usually smooth, though some species have an interior septum. Keyhole Limpets have no operculum or periostracum. Their mantle may cover some, or most, of the shell. They have a strong foot that allows them to cling tightly to rocks and other hard surfaces. The largest species in this family reach 13.2 cm (5.2 inches) in length.
Habitat and Distribution: Keyhole Limpets are found attached to hard surfaces, often in turbulent waters. They live in the intertidal zone, and to depths exceeding 1,000 m (3,280 feet). Keyhole Limpets are found in temperate to tropical seas. At least twenty species from the Fissurellidae Family are found in Mexican waters.
Natural History: There is significant diversity within the Fissurellidae Family in terms of morphology and behavior. Some species use their strong foot and streamline profile to live in areas of heavy surf and surge. Others are found in calm deep waters. Keyhole Limpets eat a variety of foods including, algae, detritus, and sponges, In turn, they are preyed upon by shorebirds, crabs, fish, sea stars, and seals. Their utilize camouflage and a hard shell to avoid predation. One Keyhole Limpet species has a symbiotic relation with a polychaete worm where the worm receives protection under the Keyhole Limpet’s shell, and, in return, the worm bites the tube feet of attacking sea stars. Keyhole Limpets are gonochoric, but reproduce by different strategies. Most species reproduce through broadcast spawning but others use internal or indirect fertilization. Keyhole Limpets are edible and larger species are harvested for food. Some are also harvested for fish bait. Some species contain a protein called Keyhole Limpet Hemocyanin (KLH), which is used in medical research, as an immune stimulant, and a carrier protein for vaccines.