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 ?
Finally, this study presented the first documented cases of abnormalities for Fissurella, several species of chitons, and overall octopuses from the South Pacific, and the first recorded case on abnormalities in internal organs of cephalopods.
Caption: Armored plates on the backs of these West Indian fuzzy chitons not only protect the soft mollusk flesh underneath but also see rough images thanks to hundreds of small, embedded eyes (inset).
At present, we can say little about endemism of chitons for the Sao Tome and Principe Islands.
The paper is focused on the gumboot chiton, the largest type of chiton, which can be up to a foot-long.
Key words: traditional knowledge, fieldwork, collaborative fieldwork, ecology, black leather chiton, Katharina tunicata, sea ice, collaboration, Alutiiq, Inuit
The teeth of chitons and limpets are among the most complex wear-resistant structures to have evolved within the animal kingdom.
Among the many studies of aesthete canals in modern chitons, those of Fernandez and others (2007) and Vendrasco and others (2008) are most instructive to the present study.
Piet Kaas and Richard Van Belle began their project of describing and illustrating every known species of chitons in 1985 with the first volume of their Monograph of Living Chitons series and continued with four subsequent volumes until Kaas' death in 1996.
This debris may bury small, sessile organisms such as anemones and tunicates, and may restrict movement or distribution of organisms that live on rock surfaces (chitons, snails, and limpets).
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.