Polychaeta is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm and the sandworm or clam worm Alitta.
The blow lugworm, also known as sandworm, is a large species of marine worm. Its coiled castings are a familiar sight on a beach at low tide but the animal itself is rarely seen except by those who, from curiosity or to use as fishing bait, dig the worm out of the sand.
Haplodrili, or Archiannelida, is an order of primitive polychaete worms. Zoologist Ray Lankester gave it the name haplodrili, while zoologist Berthold Hatschek later named it Archiannelida. Once considered to be a class under Annelida, and even a separate phylum, Haplodrili is now widely accepted to be an order under Polychaeta. Species in this order are known for completely lacking external segments.
Nereididae are a family of polychaete worms. It contains about 500 – mostly marine – species grouped into 42 genera. They may be commonly called ragworms or clam worms.
Pectinariidae, or the trumpet worms or ice cream cone worms, are a family of marine polychaete worms that build tubes using grains of sand roughly resembling ice cream cones or trumpets. These structures can be up to 5 centimetres (2 in) long. The earliest pectinariid fossils are known from the Cretaceous.
Sabellidae, or feather duster worms, are a family of marine polychaete tube worms characterized by protruding feathery branchiae. Sabellids build tubes out of a tough, parchment-like exudate, strengthened with sand and bits of shell. Unlike the other sabellids, the genus Glomerula secretes a tube of calcium carbonate instead. Sabellidae can be found in subtidal habitats around the world. Their oldest fossils are known from the Early Jurassic.
Eunicida is an order of polychaete worms.
Hydroides norvegica is a species of tube-forming annelid worm in the family Serpulidae. It is found on submerged rocks, shells, piles and boats in many coastal areas around the world. It is the type species of the genus Hydroides.
Spirorbis borealis is a sedentary marine polychaete worm in the Serpulidae family. It is commonly called the sinistral spiral tubeworm and is the type species of the genus Spirorbis.
Sabellastarte spectabilis is a species of benthic marine polychaete worm in the Sabellidae family. It is commonly known as the feather duster worm, feather duster or fan worm. It is native to tropical waters of the Indo-Pacific but has spread to other parts of the world. It is popular in aquariums because of its distinctive appearance and its ability to remove organic particles and improve water quality.
Cirratulus cirratus is a species of marine polychaete worm in the family Cirratulidae. It occurs in the littoral and sub-littoral zones of the Atlantic Ocean.
Cirratulidae is a family of marine polychaete worms. Members of the family are found worldwide, mostly living in mud or rock crevices. Most are deposit feeders, but some graze on algae or are suspension feeders.
Lanice conchilega, commonly known as the sand mason worm, is a species of burrowing marine polychaete worm. It builds a characteristic tube which projects from the seabed, consisting of cemented sand grains and shell fragments with a fringe at the top.
Abarenicola pacifica or the Pacific lugworm is a large species of polychaete worm found on the west coast of North America and also in Japan. The worms live out of sight in burrows under the sand and produce casts which are visible on the surface.
The Onuphidae are a family of polychaete worms.
Pilargidae is a family of polychaetes. These marine worms are cylindrical, somewhat flattened, and can be ribbon-like. They can be found free-living on sediment, or shallowly in sediment. Some species within the genera Hermundura and Litocorsa are known to burrow, having reduced heads and parapodia. Two species are known to be commensal with other polychaetes. Pilargis berkeleyae will live in the tubes of Chaetopteridae, and Ancistrosyllis commensalis will live in Capitellidae burrows. Pilargid worms are almost all exclusively predators, classified as carnivore omnivores. They are similar in appearance to Hesionidae, with a peristomium often with two pairs of tentacular cirri, reduced or absent notopodia, and a lack of pharyngeal jaws. The first few segments bearing setigers are also somewhat fused. They can have 0 to 3 antennae, and palps. These polychaetes are rarely the most abundant polychaete.
Sternaspidae, commonly known as mud owls, are a family of marine polychaete worms with short swollen bodies. They have a global distribution and live buried in soft sediment at depths varying from the intertidal zone to 4,400 m (14,400 ft).
Maldanidae is a family of more than 200 species of marine polychaetes commonly known as bamboo worms or maldanid worms. They belong to the order Capitellida, in the phylum Annelida. They are most closely related to family Arenicolidae, and together form the clade Maldanomorpha.
Abarenicola affinis is a species of polychaetes belonging to the family Arenicolidae.
Diopatra claparedii is a species of tube-building polychaete worm of the family Onuphidae. It is found dispersed along intertidal and subtidal benthic environments of South Asian waters, especially along the coasts of Malaysia, Singapore, Thailand, and the Philippines. This species is exploited by humans for fishing bait, indication of marine pollution, and as gold and silver nanoparticle biosynthesis agents.
