Barnacles are arthropods of the subclass Cirripedia in the subphylum Crustacea. They are related to crabs and lobsters, with similar nauplius larvae. Barnacles are exclusively marine invertebrates; many species live in shallow and tidal waters. Some 2,100 species have been described.
Balanus is a genus of barnacles in the family Balanidae of the subphylum Crustacea.
The Chthamalidae are a family of chthamaloid barnacles, living entirely in intertidal/subtidal habitats, characterized by a primary shell wall of eight, six, or four plates, lacking imbricating plate whorls, and either membraneous or more rarely calcareous basis. They are not found below immediate subtidal habitats, and more likely are found in the highest tier of shallow-water barnacle fauna. They can be found in the most rigorous wave-washed locations, and some species are found in the surf zone above high tide mark, only receiving water from wave action at high tide. The family includes at least 56 recognized species.
Menesiniella aquila is a species of acorn barnacle in the family Balanidae. It is found off the California coast from San Francisco to San Diego from the bottom of the intertidal zone down to depths of 18 m. It is preyed upon by fish, sea stars, and certain carnivorous snails. Fish also rub against the barnacles to clean themselves of parasites, which wears the barnacles shells to a smooth surface.
Acorn barnacle and acorn shell are vernacular names for certain types of stalkless barnacles, generally excluding stalked or gooseneck barnacles. As adults they are typically cone-shaped, symmetrical, and attached to rocks or other fixed objects in the ocean. Members of the barnacle order Balanomorpha are often called acorn barnacles.
Semibalanus balanoides is a common and widespread boreo-arctic species of acorn barnacle. It is common on rocks and other substrates in the intertidal zone of north-western Europe and both coasts of North America.
Whale barnacles are species of acorn barnacle that belong to the family Coronulidae. They typically attach to baleen whales, and sometimes settle on toothed whales. The whale barnacles diverged from the turtle barnacles about three million years ago.
Megabalanus is a genus of barnacles in the family Balanidae. Members of the genus grow to 7 cm (2.8 in) in length and inhabit the lower intertidal zone.
Balanus nubilus, commonly called the giant acorn barnacle, is the world's largest barnacle, reaching a diameter of 15 cm (6 in) and a height of up to 30 cm (12 in), and containing the largest known muscle fibres.
Amphibalanus improvisus, the bay barnacle, European acorn barnacle, is a species of acorn barnacle in the family Balanidae.
Hypsoblennius invemar, commonly known as the tessellated blenny, is a species of combtooth blenny found in the western Atlantic Ocean.
Balanus balanus is a species of acorn barnacle in the Balanidae family. It is native to the colder seas of the northern hemisphere.
Balanus crenatus is a species of acorn barnacle in the Balanidae family. It is found in the North Pacific and the North Atlantic Ocean.
Amphibalanus amphitrite is a species of acorn barnacle in the Balanidae family. Its common names include the striped barnacle, the purple acorn barnacle and Amphitrite's rock barnacle. It is found in warm and temperate waters worldwide.
Balanus perforatus is a species of barnacle in the family Balanidae. It is found on the lower shore and in the neritic zone in the warm temperate parts of the eastern Atlantic Ocean.
Megabalanus stultus is a species of barnacle first described by Charles Darwin in 1854. It lives on fire corals of the genus Millepora in the Atlantic Ocean from Florida to southern Brazil.
Balanus trigonus is a species of barnacle in the family Balanidae. It is steep-sided, conical barnacle, has six shell plates and is pink in colour. They are opportunistic fouling organisms that are endemic to the Indo-Pacific region.
Amphibalanus eburneus, the ivory barnacle or American acorn barnacle, is a species of acorn barnacle in the family Balanidae. It occurs on the east coast of North America, the Caribbean Sea and Gulf of Mexico.
Megabalanus coccopoma, the titan acorn barnacle, is a tropical species of barnacle first described by Charles Darwin in 1854. Its native range is the Pacific coasts of South and Central America but it is extending its range to other parts of the world.
Megabalanus azoricus, the Azorean barnacle, is a species of large barnacle in the family Balanidae. It is endemic to Macaronesia: the Azores, Madeira, the Canary Islands, and Cape Verde. It is the largest and third most common shallow water barnacle of the Azores, where it is heavily exploited for food and has a high commercial value since the colonization of the islands. It was included in the 100 species for priority management within Macaronesia. It is a thoracopodal filter feeder and the majority are hermaphrodites. It is more abundant in the first 3 m (9.8 ft) on the low intertidal and infralittoral rocky shores. The empty shells of the barnacles are a vital habitat for the blennies Parablennius ruber, P. incognitus and Coryphoblennius galerita as they provide shelter and substrata for egg deposition during reproduction. A large number of invertebrate species also use the empty shells. Although present throughout the archipelago, it is more abundant in the eastern islands. It has a genetic similarity with Megabalanus tintinnabulum. Some crucial features of the M. azoricus species are digonic hermaphroditism in sessile adults, development of planktotrophic larvae, dependence on exposed rocky shores in the intertidal habitat, and insular distribution restricted to the northeastern Atlantic oceanic islands.
