Tetraclitidae Family of Volcano Barnacles

One Volcano Barnacle of the Tetraclitidae Family can be found in this website:

Volcano Barnacle, Tetraclita stalactifera. A representative of the Tetraclitidae Family of Volcano Barnacles.

Volcano Barnacles are members of the Tetraclitidae Family. The taxonomy of the Tetraclitidae Family is a fluid and complex one, with many sub, super, and infra levels.  Because Volcano Barnacles live in a cone-shaped shell, attached to rock, it is easy to think that they may be a type of shell bearing Mollusk. Actually, they are in the Phylum Arthropoda, meaning that they have jointed legs, and are crustaceans, the same as crabs and lobsters. They are in the Class Hexanauplia, along with copepods.

The Volcano Barnacles are in the Infraclass Cirripedia, the barnacles. Barnacles have a carapace that completely encloses the entire body. In most cases, the carapace secretes a chitinous shell. Being enclosed in this shell, barnacles either lack, or have reduced, compound eyes, abdomens, and appendages. Barnacles so enclosed in a shell are in the Order Sessilia. Other Cirripeds include stalked barnacles and parasitic barnacles.

Volcano Barnacles begin life as planktonic, shrimp-like larvae. When they are ready to settle out, the larvae become highly selective in location as once they attach to a hard surface, these animals are unable to change locations. There may be up to 70,000 larvae per square meter in a quality location that have to compete with algae, limpets, and mussels that occupy the same area. They glue their head to a crab, pier piling, rock, turtle, or other hard surface. They then secrete a chitin shell around them. Chitin is the same material that crab and lobster shell is made from. The shell consists of four plates fused together, in the shape of a volcano. When the animal is submerged it extends its feathery feet through the top of the volcano. These feet function like gills to extract oxygen from the water, and they also filter plankton and detritus from the water for food. In turn they are preyed upon by crabs, fish, gastropods, and starfish. Volcano Barnacles can reach a maximum of 5.0 cm (2.0 inches) in diameter.

Volcano Barnacles reside worldwide in tropical and temperate seas. They are found from the intertidal zone to depths in excess of 2,000 m (6,560 feet).

They Tetraclitid are found worldwide in tropical and temperate seas. There are forty-three species in the Tetraclitidae Family or which two species are found along the Pacific Coast of Mexico.