Any of about 5,400 species of marine worms of the annelid class Polychaeta, having a segmented body with many setae (bristles) on each segment. Species, often brightly coloured, range from less than 1 in. (2.5 cm) to about 10 ft (3 m) long. Most body segments bear two bristly parapodia (lobelike outgrowths). The head has short sensory projections and tentacles. Adults may be free-swimming or sedentary; larvae are free-swimming. Found worldwide, polychaetes are important for turning over sediment on the ocean bottom. One species, the bloodworm, is a popular saltwater fish bait. Seealso tube worm.
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The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed the polychaetes are sometimes referred to as bristle worms. More than 10,000 species are described in this class. Common representatives include the lugworm (Arenicola marina) and the sandworm or clam worm Nereis.
A few groups have evolved to live in terrestrial environments, like Namanereidinae with many terrestrial species, but are restricted to humid areas. Some have even evolved cutaneous invaginations for aerial gas exchange.
Much of the classification below matches Rouse & Fauchald, 1998, although that paper does not apply ranks above family.
Older classifications recognize many more (sub)orders than the layout presented here. As comparatively few polychaete taxa have been subject to cladistic analysis, some groups which are usually considered invalid today may eventually be reinstated.
Control of shell-boring polychaetes in Haliotis tuberculata coccinea (reeve 1846) aquaculture: species identification and effectiveness of mebendazole.(Report)
Aug 01, 2011; ABSTRACT The experimental culture of Haliotis tuberculata coccinea is carried out at the Institute of Marine Science of Canary...
First report of polychaetes from the genus Oriopsis (polychaeta: Sabellidae) associated with the Japanese abalone Haliotis discus hannai and other native molluscs in Chile.(Report)
Sep 01, 2007; ABSTRACT The external morphology of sabellids polychaetes gathered from green abalone (H. discus hannai) and 2 species of...