Pomatoceros triqueter

Pomatoceros triqueter
	Calcareous tubes on boulder
Scientific classification
Kingdom:	Animalia
Phylum:	Annelida
Class:	Polychaeta
Order:	Canalipalpata
Family:	Serpulidae
Genus:	Pomatoceros
Species:	P. triqueter
Binomial name
	Pomatoceros triqueter; (Linnaeus, 1758)
Synonyms
	Serpula triquetraLinnaeus, 1758 [1] ;

Last updated May 02, 2019

Pomatoceros triqueter is a species of tube-building annelid worm in the class Polychaeta. It is common on the north eastern coasts of the Atlantic Ocean and in the Mediterranean Sea.

In biology, a species ( ) is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, and in a ring species. Also, among organisms that reproduce only asexually, the concept of a reproductive species breaks down, and each clone is potentially a microspecies.

The annelids, also known as the ringed worms or segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments.

In biological classification, class is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order.

Polychaetes, or marine bristle worms, have elongated bodies divided into many segments. Each segment may bear setae (bristles) and parapodia (paddle-like appendages). Some species live freely, either swimming, crawling or burrowing, and these are known as "errant". Others live permanently in tubes, either calcareous or parchment-like, and these are known as "sedentary".

Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, and Annelida. These three groups form segments by using a "growth zone" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this patterning. Even within these groups, different organisms have different mechanisms for segmenting the body. Segmentation of the body plan is important for allowing free movement and development of certain body parts. It also allows for regeneration in specific individuals.

The term parapodium refers to two different organs. In annelids, parapodia are paired, un-jointed lateral outgrowths that bear the chaetae. In several groups of sea snails and sea slugs, 'parapodium' refers to lateral fleshy protrusions.

Distribution

This species is found in the Arctic, eastern North Atlantic, the Mediterranean, Adriatic, Black and Red Sea, the English Channel, the North Sea, Skagerrak, Kattegat the Little and Great Belts and Øresund north east to the Bay of Kiel.

The Arctic is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Alaska, Finland, Greenland (Denmark), Iceland, Northern Canada, Norway, Russia and Sweden. Land within the Arctic region has seasonally varying snow and ice cover, with predominantly treeless permafrost -containing tundra. Arctic seas contain seasonal sea ice in many places.

The Atlantic Ocean is the second largest of the world's oceans, with an area of about 106,460,000 square kilometers. It covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. It separates the "Old World" from the "New World".

The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Southern Europe and Anatolia, on the south by North Africa and on the east by the Levant. Although the sea is sometimes considered a part of the Atlantic Ocean, it is usually identified as a separate body of water. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccated over a period of some 600,000 years, the Messinian salinity crisis, before being refilled by the Zanclean flood about 5.3 million years ago.

Description

Pomatoceros triqueter secretes a white calcareous tube about three millimetres wide and up to twenty five millimetres long. It is smooth and usually curved with a single ridge in the middle that ends in a projection over the anterior opening. The operculum has a shallow, dish-shaped plug. The body of the worm is brightly coloured and the crown of radioles is banded with various colours. The body and crown can be withdrawn into the protective tube.^[2] It is closely related to, and often confused with, Pomatoceros lamarckii .

In the bryozoan order Cheilostomata, the operculum is a calcareous or chitinous lid-like structure that protects the opening through which the polypide protrudes.

A radiole is a heavily ciliated feather-like tentacle found in highly organized clusters on the crowns of Canalipalpata. Canalipalpata is an order of sessile marine polychaete worms consisting of 31 families. These benthic annelid tube worms employ radioles primarily for alimentation. While their primary role is to function as an organ for filter feeding, radioles also serve as respiratory organs. Because of their role in gas exchange, radioles are often referred to as "gills".

<i>Pomatoceros lamarckii</i> Species of annelid

Pomatoceros lamarckii is a species of tube-building annelid worms which is widespread in intertidal and sub-littoral zones around the United Kingdom and northern Europe. They are found attached to firm substrates, from rocks to animal shells to man made structures, and often are noted for their detrimental effect on shipping. It is closely related to, and often confused with, Pomatoceros triqueter.

Biology

Pomatoceros triqueter never leaves its tube. The action of cilia creates currents which circulate down the length of the tube. Respiration occurs when dissolved oxygen enters through the surface of the body and through the extended branchial crown. This tube worm is a filter feeder and cilia on the branchial filaments waft particles towards the central mouth. The particles are not sorted and any that are too large are removed from the mouth opening by the tip of a filament.^[2] There is a complete digestive system and like other polychaetes, P. triqueter excretes with the help of fully developed nephridia.^[3]

A cilium is an organelle found on eukaryotic cells and are slender protuberances that project from the much larger cell body.

Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O^₂. Diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. As compounds including oxides, the element makes up almost half of the Earth's crust.

Filter feeder a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure

Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish. Some birds, such as flamingos and certain species of duck, are also filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms.

Pomatoceros triqueter males release spermatogonia or primary spermatocytes into the sea and females release primary oocytes. The larvae form part of the zooplankton for two to three weeks in the summer when the majority of the breeding takes place, but for up to two months in the winter. The larvae then settle on the substrate and build a temporary delicate, semi-transparent tube formed of mucus and calcareous matter.^[4] This is later hardened by a secretion of calcium carbonate from the collar and grows at the rate of 1.5 millimetres per month.^[2] Although it may superficially give the appearance of being formed in bands, this is caused by spurts in growth interspersed with quiescent periods.^[4]^[5]

A spermatogonium is an undifferentiated male germ cell. Spermatogonia undergo spermatogenesis to form mature spermatozoa in the seminiferous tubules of the testis.

Spermatocytes are a type of male gametocyte in animals. They derive from immature germ cells called spermatogonia. They are found in the testis, in a structure known as the seminiferous tubules. There are two types of spermatocytes, primary and secondary spermatocytes. Primary and secondary spermatocytes are formed through the process of spermatocytogenesis.

An oocyte, oöcyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell (PGC), which then undergoes mitosis, forming oogonia. During oogenesis, the oogonia become primary oocytes. An oocyte is a form of genetic material that can be collected for cryoconservation. Cryoconservation of animal genetic resources have been put into action as a means of conserving traditional livestock.

Related Research Articles

{{Paraphyletic group Support and Locomotion Polychaeta. Polychaetes provide a classic example of the employment of coelomic spaces as a hydrostatic skeleton for body support. Coupled with the well developed musculature, the metameric body plan, and the parapodia, this hydrostatic quality provides the basis for understanding locomotion in these worms. We begin a survey of locomotor patterns by examining Nereis, an errant, homonomous polychaete. Keep in mind that in such polychaetes the intersegmental septa are functionally complete, and thus the coelomic spaces in each segment can be effectively isolated hydraulically from each other. Modifications on this fundamental arrangement are discussed later. In addition to burrowing, Nereis can engage in three basic epibenthic locomotor patterns: slow crawling, rapid crawling, and rather inefficient swimming. All of these methods of movement depend primarily on the bands of longitudinal muscles, especially the larger dorsolateral bands, and on the parapodial muscles. The circular muscles are relatively thin and serve primarily to maintain adequate hydrostatic pressure within the coelomic compartments. Each method of locomotion in Nereis involves the antagonistic action of the longitudinal muscles on opposite sides of the body in each segment. During movement, the longitudinal muscles on one side of any given segment alternately contract and relax in opposing synchrony with the action of the muscles on the other side of the segment. Thus, the body is thrown into undulations that move in metachronal waves from posterior to anterior. Variations in the length and amplitude of these waves combine with parapodial movements to produce the different patterns of locomotion. The parapodia and their chaetae are extended maximally in a power stroke as they pass along the crest of each metachronal wave. Conversely, the parapodia and chaetae retract in the wave troughs during their recovery stroke. Thus, the parapodia on opposite sides of any given segment are exactly out of phase with one another. When Nereis is crawling slowly, the body is thrown into a high number of metachronal undulations of short wavelength and low amplitude. The extended parapodial chaetae on the wave crests are pushed against the substratum and serve as pivot points as the parapodium engages in its power stroke. As the parapodium moves past the crest, it is retracted and lifted from the substratum as it is brought forward during its recovery stroke. The main pushing force in this sort of movement is provided by the parapodial muscles. During rapid crawling, much of the driving force is provided by the longitudinal body wall muscles in association with the longer wavelength and greater amplitude of the body undulations, which accentuate the power strokes of the parapodia. Nereis can leave the substratum to engage in a rather inefficient swimming behavior. In swimming, the metachronal wavelength and amplitude are even greater than they are in rapid crawling. When watching a nereid swim, however, one gets the impression that the “harder it tries” the less progress it makes, and there is some truth to this. The problem is that, even though the parapodia act as paddles pushing the animal forward on their power strokes, the large metachronal waves continue to move from posterior to anterior and actually create a water current in that same direction; this current tends to push the animal into reverse. The result is that Nereis is able to lift itself off the substratum, but then largely thrashes about in the water. This behavior is used primarily as a short-term mechanism to escape benthic predators rather than as ameans to get from one place to another. With these basic patterns and mechanisms in mind, we consider a few other methods of locomotion in polychaetes. Nephtys superficially resembles Nereis, but its methods of movement are significantly different. Although Nephtys is less efficient than Nereis at slow walking, it is a much better swimmer; it is also capable of effective burrowing in soft substrata. The large, fleshy parapodia serve as paddles, and, when swimming, Nephtys does not produce long, deep metachronal waves. Rather, the faster it swims, the shorter and shallower the waves become, thus eliminating much of the counterproductive force described for Nereis. When initiating burrowing, Nephtys swims head-first into the substratum, anchors the body by extending the chaetae laterally from the buried segments, and then extends the proboscis deeper into the sand. A swimming motion is then employed to burrow deeper into the substratum. In contrast to the above descriptions, scale worms have capitalized on the use of their muscular parapodia as efficient walking devices. The body undulates little if at all, and there is a corresponding reduction in the size of the longitudinal muscle bands and their importance in locomotion. In fact, these worms depend almost entirely on the action of the parapodia for walking; polynoids cannot swim. Many of the highly efficient burrowers have secondarily lost most of the intersegmental septa, or have septa that are perforated. The loss of complete septa means that segments are not of constant volume; in other words, a loss of coelomic fluid from one body region causes a corresponding gain in another. These polychaetes have reduced parapodia. The chaetae, or simply the surface of the expanded portions of the body, serve as anchor points, while the burrow wall provides an antagonistic force resisting the hydraulic pressure. In Polyphysia, peristaltic waves move constricted body regions forward while the anchored parts provide leverage. The constricted areas are reduced both in diameter and in length by simultaneous contraction of both the circular and the longitudinal muscles. Arenicola burrows first embedding and anchoringlongitudinal Arenicola burrows by first embedding and anchoring the anterior body region in the substratum. The anchoring is accomplished by contracting the circular muscles of the posterior portion of the body, thus forcing coelomic fluid anteriorly and causing the first few segments to swell. Then the posterior longitudinal muscles contract, thereby pulling the back of the worm forward. To continue the burrowing, a second phase of activity is undertaken. As the anterior circular muscles contract and the longitudinal bands relax, the posterior edges of each involved segment are protruded as anchor points to prevent backward movement; the proboscis is thrust forward, deepening the burrow. Then the proboscis is retracted, the front end of the body is engorged with fluid, and the entire process is repeated. Different burrowing mechanisms are known among other polychaetes. For example, Glycera, a long, sleek worm, burrows rapidly using its large, muscular proboscis almost exclusively. The proboscis is thrust into the substratum and swelled; then the body is drawn in by contraction of the proboscis muscles. Most tube-dwelling polychaetes are heteronomous and have rather soft bodies and relatively weak muscles. The parapodia are reduced, so the chaetae are used to position and anchor the animal in its tube. Movement within the tube is usually accomplished by slow peristaltic action of the body or by chaetae movements. When the anterior end is extended for feeding, it may be quickly withdrawn by special retractor muscles while the unexposed portion of the body is anchored in the tube. Polychaete tubes provide protection as well as support for these soft-bodied worms, and also keep the animal oriented properly in relation to the substratum. Some polychaetes build tubes composed entirely of their own secretions. Most notable among these tube builders are the serpulids and spirorbids, which construct their tubes of calcium carbonate secreted by a pair of large glands near a fold of the peristomium called the collar. The crystals of calcium carbonate are added to an organic matrix; the mixture is molded to the top of the tube by the collar fold and held in place until it hardens. Some sabellids produce parchment-like or membranous tubes of organic secretions molded by the collar. Others, such as Sabella, mix mucous secretions with size selected particles extracted from feeding currents, then lay down the tube with this material. Numerous other polychaete groups form similar tubes of sediment particles collected in various ways and cemented together with mucus. A few polychaetes are able to excavate burrows by boring into calcareous substrata, such as rocks, coral skeletons or mollusc shells. In extreme situations, the activity of the polychaetes may have deleterious effects on the “host.” For example, species of Polydora (Spionidae) can cause serious damage to commercially raised oysters. Many sedentary polychaetes use modifications of the basic locomotor actions described above to provide means of moving water through their tubes or burrows. Some of these modifications are discussed in the sectionon feeding.

Sabellidae 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.

Serpula is a genus of sessile, marine annelid tube worms that belongs to the family Serpulidae. Serpulid worms are very similar to tube worms of the closely related sabellid family, except that the former possess a cartilaginous operculum that occludes the entrance to their protective tube after the animal has withdrawn into it. The most distinctive feature of worms of the genus Serpula is their colorful fan-shaped "crown". The crown, used by these animals for respiration and alimentation, is the structure that is most commonly seen by scuba divers and other casual observers.

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.

Chaetopterus variopedatus is a species of parchment worm, a marine polychaete in the family Chaetopteridae. It is found worldwide. However, recent discoveries from molecular phylogeny analysis show that Chaetopterus variopedatus sensu Hartman (1959) is not a single species.

Amphitrite ornata or ornate worm, is a species of marine polychaete worm in the family Terebellidae.

Cirratulus cirratus is a species of marine polycheate 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.

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.

<i>Eudistylia polymorpha</i> Species of annelid

Eudistylia polymorpha, the giant feather duster worm, is a species of marine polychaete worm belonging to the family Sabellidae. Its common name is from the crown of tentacles extended when the animal is under water.

Serpula vermicularis, known by common names including the calcareous tubeworm, fan worm, plume worm or red tube worm, is a species of segmented marine polychaete worm in the family Serpulidae. It is the type species of the genus Serpula and was first described by Linnaeus in 1767. It lives in a tube into which it can retract.

Neosabellaria cementarium is a species of marine tube worm in the family Sabellariidae, perhaps better known by its previous name, Sabellaria cementarium. It is found in the North Pacific Ocean.

Eunice norvegica is an aquatic polychaete worm found in deep water on the seabed of the northern Atlantic Ocean as well as in the Pacific and Indian Oceans. It is a tubeworm and is often associated with deep water corals.

Phyllodoce mucosa is a species of polychaete worm in the family Phyllodocidae. It is found intertidally in both the Pacific and Atlantic Oceans, typically on sandy or muddy seabeds.

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.

Serpula columbiana, variously called the calcareous tubeworm, the plume worm, the fan worm, the limy tube worm and the red tube worm, is a species of segmented marine polychaete worm in the family Serpulidae. It is a cosmopolitan species that is found in most seas in the Northern Hemisphere including the Atlantic Ocean, the Pacific Ocean and the Indian Ocean.

References

↑ Marine Species Identification Portal
1 2 3 Marine Life Information Network Archived 2012-04-02 at the Wayback Machine
↑ Jean Hanson (1949). "Observations on the Branchial Crown of the Serpulidae (Annelida, Polychaeta)". Quarterly Journal of Microscopical Science. 90 (s3): 221–233. Retrieved 2010-11-25.
1 2 Segrove, F., 1941. The development of the serpulid Pomatoceros triqueter, Quart. J. micr. Sci., Vol. 82, pp. 467-540.
↑ Tube formation by Pomatoceros triqueter (Polychaeta)

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[1] Marine Species Identification Portal

[MarLIN-2] 1 2 3 Marine Life Information Network Archived 2012-04-02 at the Wayback Machine

[Hanson221-3] Jean Hanson (1949). "Observations on the Branchial Crown of the Serpulidae (Annelida, Polychaeta)". Quarterly Journal of Microscopical Science. 90 (s3): 221–233. Retrieved 2010-11-25.

[Segrove-4] 1 2 Segrove, F., 1941. The development of the serpulid Pomatoceros triqueter, Quart. J. micr. Sci., Vol. 82, pp. 467-540.

[5] Tube formation by Pomatoceros triqueter (Polychaeta)