Acanthochitonidae is a family of marine

mollusks Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The num ...

belonging to the class Polyplacophora, commonly known as chitons. Species are widely distributed throughout the world's oceans, but are most commonly found in the shallow waters of the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

, from

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

Description

Acanthochitonidae are characterized by a broad girdle covered in coarse spines with erect tufts of up to ten large bristles. The coarsely granular valves of the shell are partially overlapped by the girdle. The articulating

flange A flange is a protruded ridge, lip or rim (wheel), rim, either external or internal, that serves to increase shear strength, strength (as the flange of a steel beam (structure), beam such as an I-beam or a T-beam); for easy attachment/transfer o ...

, or articulamentum, is well developed. The margin of the cephalic plate has about five slits, and the lateral insertion plates all have a single notch. These small to large chitons have a distinctive appearance, and are easily recognizable by their characteristic spiny girdle.

Habitat

Acanthochitonidae chitons are found in a variety of marine habitats, including rocky intertidal zones, coral reefs, and seagrass beds. They are also found in deep sea environments, with some species occurring as deep as 3,000 meters. Acanthochitonidae chitons are known to be active grazers, feeding primarily on algae and

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

Reproduction

Like other chitons, Acanthochitonidae are dioecious, meaning they have separate sexes. Fertilization is external, with males releasing sperm into the water, which is then taken in by females. The eggs are then fertilized internally and laid in capsules that are cemented to hard surfaces.

Ecological significance

Acanthochitonidae chitons play an important role in marine ecosystems, serving as grazers and helping to maintain the balance of marine communities. They are preyed upon by a variety of predators, including sea stars, crabs, and fish.

Conservation

Several species of Acanthochitonidae chitons are of conservation concern, particularly in areas where they are heavily harvested for food or decorative purposes. In some regions, they are also threatened by

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and pollution.

Taxonomy

The family Acanthochitonidae includes approximately 80 species, distributed across 13

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

. Taxonomic classification within this family has been a subject of debate, with some species being moved between genera or reassigned to other families. Molecular phylogenetic studies have helped to clarify the relationships between different

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

within the family, and have led to the establishment of several new genera.

Genera

According to the

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

(WoRMS) the following genera are included in this family:WoRMS : Acanthochitonidae
/ref> ; † '' Afossochiton'' Ashby, 1925 ; † '' Lirachiton'' Ashby & Cotton, 1939 : '' Sulcichiton'' Sirenko, 2021 ;Subfamily Acanthochitoninae Pilsbry, 1893 * '' Acanthochitona'' Gray, 1821 * '' Americhiton'' Watters, 1990 * '' Bassethullia'' Pilsbry, 1928 * '' Choneplax'' Carpenter MS, Dall, 1882 * '' Craspedochiton'' Shuttleworth, 1853 * '' Craspedoplax'' Iredale & Hull, 1925 * '' Cryptoconchus'' de Blainville MS, Burrow, 1815 * '' Leptoplax'' Carpenter MS, Dall, 1882 * ''

Notoplax ''Notoplax'' is a genus of chitons in the family Acanthochitonidae.Bouchet, P.; Schwabe, E. (2012). Notoplax. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=206244 on 2012-04-17 Speci ...

'' H. Adams, 1862 * † '' Pseudoacanthochitona'' Šulc, 1934 * '' Pseudotonicia'' Ashby, 1928 ;Subfamily Cryptochitoninae Pilsbry, 1893 * '' Cryptochiton'' Middendorff, 1847

References

* Vaught, K.C. (1989). A classification of the living Mollusca. American Malacologists: Melbourne, FL (USA). . XII, 195 pp {{Authority control Chiton families