chiton

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chiton

(kī`tən), common name for rock-clinging marine mollusks of the class Polyplacophora. Chitons are abundant on rocky coasts throughout most of the world, from the intertidal zone to a depth of about 1,200 ft (400 m). They range in length from 1-2 in. to 12 in. (1.2–30 cm), according to the species, but most are 1 to 3 in. (2.5–7.5 cm) long. The body of a chiton is low and oval; it is covered dorsally by a slightly convex shell consisting of eight linearly arranged overlapping plates. The shell may be dull or brightly colored. Most of the lower surface consists of a broad, flat foot with which the chiton clings to hard surfaces, often so tightly that a sharp instrument is needed to pry it loose. When dislodged, a chiton rolls into a ball. Beneath the shell is the characteristic molluscan mantle, a fleshy outfolding of the body wall. The lower edge of the mantle, called the girdle, extends below the edge of the shell and aids the foot in gripping. The girdle may be very wide and extend upward over the shell; in some species it is smooth or covered with scales, hairs, or spines that give the animal a shaggy appearance. The many gills are arranged in two rows within the mantle, one on either side of the body. The mouth, located on the ventral surface in front of the foot, contains a toothed, tonguelike scraping organ, the radula. Chitons crawl slowly by means of muscular undulations in the foot. Most are herbivorous, feeding on algae scraped from rocks and shells with the radula; some are carnivorous or omnivorous. Most feed at night and shelter under rock ledges by day. Chitons are classified in the phylum MolluscaMollusca
, taxonomic name for the one of the largest phyla of invertebrate animals (Arthropoda is the largest) comprising more than 50,000 living mollusk species and about 35,000 fossil species dating back to the Cambrian period.
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, class Polyplacophora, order Polyplacophora.

chiton

[′kīt·ən]
(invertebrate zoology)
The common name for over 600 extant species of mollusks which are members of the class Polyplacophora.
References in periodicals archive ?
Vertical distribution of chitons (Mollusca: Polyplacophora) in the rocky intertidal zone of central Chile.
Researchers could tell because chitons clamped their shells defensively to the bottom when a scary circle appeared but not when an artificial sky turned overall shadowy.
The intermediate typical tropical regions with warm water and reduced salinity are unlikely to be a distributional barrier for the chitons, if patterns demonstrated for other benthic marine invertebrate taxa also apply to them.
The paper is focused on the gumboot chiton, the largest type of chiton, which can be up to a foot-long.
2007), los que senalaron tres especies: Acanthopleura granulata (Gmelin, 1791), unica especie registrada para el Caribe, Chiton marmoratus (Gmelin 1971) y Chiton tuberculatus (Linnaeus 1758).
Design of the research questions, selection of the survey sites, and the actual fieldwork were carried out during successive visits in collaboration with local Alutiiq residents, who harvest the chitons (known locally as "bidarkis") and were concerned about their decline.
Chiton (Mollusca: Polyplacophora) fauna of Barbados, West Indies, with the description of a new species.
Chitons have 17 teeth in each transverse row, with a single pair being iron-mineralized.
These reports show the usefulness of determining the canal systems in chitons for taxonomic and phylogenetic studies.
Wave action and bio-erosion caused by chitons has undercut many of the outcrops, giving them a peculiar mushroom-like shape.
Its sandstone bluffs and ledges form a natural laboratory for studying marine life, and as myriad pools are exposed at low tide, sea gardens populated by purple sea urchins, giant green anemones, button-shaped limpets, leathery chitons, and ocher sea stars appear in each one.
Because the chitons occur in an intricate network of burrows (up to 10 cm deep, [ILLUSTRATION FOR FIGURE 2A, B OMITTED]; see photo on p.