| Polydora ciliata | |
|---|---|
 | |
| P. ciliata (above) | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Class: | Polychaeta |
| Order: | Spionida |
| Family: | Spionidae |
| Genus: | Polydora |
| Species: | P. ciliata |
| Binomial name | |
| Polydora ciliata | |
| Synonyms | |
| |
Polydora ciliata is a species of annelid worm in the family Spionidae, commonly known as a bristleworm. [1] It is a burrowing worm and is found in the northeastern Atlantic Ocean and some other parts of the world.
Polydora ciliata was first described in 1838 by the Scottish physician and naturalist George Johnston as Leucodore ciliatus, [2] but was later placed in the genus Polydora . A planktonic organism was described as Metadasydytes quadrimaculatus in 1971 by Roch Roszczak, who placed it in the phylum Gastrotricha; [3] it was later established that the animal he was describing was in fact the larval stage of a spionid worm, probably Polydora ciliata. [1]
The species can grow to a length of about 30 mm (1.2 in) with around 180 segments. The front of the prostomium (head) has no eyes or antennae, but the hind part has a pair of long palps and up to four eyes. The multi-segmented body is broadest fairly near the front and then tapers gradually to the pygidium (terminal segment) which bears a funnel. Each segment bears parapodia (outgrowths) and chaetae (bristles), the ventral branches of the parapodia being triangular or finger-like, and these structures reducing in size towards the rear of the animal. On segment five, the bristles are specially modified for burrowing. Gills are present on all the segments beyond 7 except for the last 10 to 20 segments. [4]
P. ciliata has a widespread distribution round the coasts of northwestern Europe. As a burrowing species, it tunnels into limestone; chalk and clay, calcareous algae, the holdfasts of seaweeds, wood, muddy sediment and mollusc shells, including those of oysters, mussels and periwinkles. [5] It is also known from the Mediterranean Sea, the Red Sea, the Black Sea, the Indo-Pacific and Antarctica. [4]
The burrow of P. ciliata is U-shaped, and the presence of these worms can be recognised by the sets of small, double perforations they make. The worm is believed to burrow by abrading the substrate with its bristly chaetae, but there may also be some chemical action involved in burrowing. The tube is lined with mucus and fine grains of sediment and extends slightly above the surrounding material. When feeding, the worm extends its head out of the tube and uses its two long palps to feed on detritus. It has been observed feeding on dead barnacles and other small dead invertebrates, and can also filter plankton from the water. [6]
The worms are either male or female; sperm is liberated into the water column and drawn into the burrow of the female by means of the respiratory current. Up to 60 eggs are enclosed in a capsule, and several capsules are suspended by threads inside the female's tube. The eggs hatch in about one week and are planktonic for up to six weeks before settling. When the worms bore into the shells of oysters, mussels and periwinkles, they do not feed on the mollusc's soft parts, but they weaken the shell and make the mollusc more vulnerable to attack by crabs and other predators. [6]
The Echiura, or spoon worms, are a small group of marine animals. Once treated as a separate phylum, they are now considered to belong to Annelida. Annelids typically have their bodies divided into segments, but echiurans have secondarily lost their segmentation. The majority of echiurans live in burrows in soft sediment in shallow water, but some live in rock crevices or under boulders, and there are also deep sea forms. More than 230 species have been described. Spoon worms are cylindrical, soft-bodied animals usually possessing a non-retractable proboscis which can be rolled into a scoop-shape to feed. In some species the proboscis is ribbon-like, longer than the trunk and may have a forked tip. Spoon worms vary in size from less than a centimetre in length to more than a metre.
The Polychaeta, also known as the bristle worms or polychaetes, are a paraphyletic 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. More than 10,000 species are described in this class. Common representatives include the lugworm and the sandworm or clam worm Alitta.
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.
Phyllodocida is an order of polychaete worms in the subclass Aciculata. These worms are mostly marine though some are found in brackish water. Most are active benthic creatures, moving over the surface or burrowing in sediments, or living in cracks and crevices in bedrock. A few construct tubes in which they live and some are pelagic, swimming through the water column. There are estimated to be about 3,500 species in the order.
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.
Lagis koreni, commonly known as the trumpet worm, is a species of marine polychaete worm found in European waters. It lives within a narrow conical tube made of grains of sand and shell fragments.
Haplosyllis spongicola, the sponge worm, is a species of polychaete worm in the family Syllidae. It was previously classified as Syllis spongicola and is part of a species complex of closely related species that are difficult to distinguish morphologically and where the demarcation between them is unclear. It is found in shallow temperate, subtropical and tropical seas worldwide, wherever its host sponges are found.
Polydora is a genus of annelid worms. It contains marine polychaete species that live in mud, holes bored in rocks, and holes bored in the shells of shellfish.
Prosphaerosyllis battiri is a species belonging to the phylum Annelida, a group known as the segmented worms. The species name comes from an Aboriginal word, battiri, meaning "rough". Prosphaerosyllis battiri is a species characterized by having only partially fused palps, an unretracted prostomium on its peristomium or showing only slight retraction, the shape of its dorsal cirri and its arrangement of papillae, being numerous anteriorly while less numerous posteriorly. It resembles Prosphaerosyllis semiverrucosa, but its arrangement of dorsal papillae is reversed.
Phyllodocidae is a family of polychaete worms. Worms in this family live on the seabed and may burrow under the sediment.
Scolelepis squamata is a species of polychaete worm in the family Spionidae. It occurs on the lower shore of coasts on either side of the Atlantic Ocean.
Neanthes fucata is a species of marine polychaete worm in the family Nereididae. It lives in association with a hermit crab such as Pagurus bernhardus. It occurs in the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea.
Polydora glycymerica is a species of annelid worm in the family Spionidae, native to the northwestern Pacific Ocean, where it lives commensally in association with a bivalve mollusc, usually Glycymeris yessoensis but occasionally with another species of clam. The worm intercepts food particles being drawn into the mollusc by its feeding current.
Poecilochaetus serpens is a species of marine polychaete worm in the family Poecilochaetidae. It is a benthic worm that burrows into soft sediment.
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).
Sternaspis scutata is a species of marine polychaete worm in the family Sternaspidae. It occurs in the Mediterranean Sea and the temperate northeastern Atlantic Ocean. It lives submerged in mud or other soft sediment.
Maxmuelleria lankesteri is a species of spoon worm in the family Bonelliidae. It is found in the North Atlantic Ocean. It burrows into soft sediment on the seabed, mostly in deep water.