Gastrotrich


Gastrotrich

Taxobox
name = Gastrotrichs



image_width = 250px
image_caption = Darkfield photograph of a gastrotrich.
regnum = Animalia
subregnum = Eumetazoa
unranked_phylum = Bilateria
superphylum = Platyzoa
phylum = Gastrotricha
phylum_authority = Metschnikoff, 1864
subdivision_ranks = Orders
subdivision =
Macrodasyida
Chaetonotida
The gastrotrichs (from Greek γαστερ, "gaster" "stomach" and θριξ, "thrix" "hair") are a phylum of microscopic (0.06-3.0 mm) animals abundant in fresh water and marine environments. Most fresh water species are part of the periphyton and benthos. Marine species are found mostly interstitially in between sediment particles. They are bilaterally symmetric, with a complete gut. They demonstrate eutely, with development proceeding to a particular number of cells, and further growth coming only from an increase in cell size. The body is covered with cilia, especially about the mouth and on the ventral surface, and has two terminal projections with cement glands that serve in adhesion. This is a double-gland system where one gland secretes the glue and another secretes a de-adhesive to sever the connection. Like many microscopic animals, their locomotion is primarily powered by hydrostatics, and they reproduce entirely by parthenogenesis. Originally they were thought to have a body cavity (pseudocoel), but this was an artifact created by preservation methods, and they are now known to be acoelomate. Their relationship to other phyla is unclear. Morphology suggests that they are close to the Gnathostomulida, the Rotifera, or the Nematoda. On the other hand genetic studies place them as close relatives of the Platyhelminthes, the Ecdysozoa or the Lophotrochozoa. About 700 species have been described. The average life span of a gastrotrich is very short - about three days.

References

* [http://www.gastrotricha.unimore.it/overview.htm University of Modena and Reggio Emilia: Gastrotricha World Portal - Overview] - URL retrieved December 3, 2006

External links

* [http://www.eol.org/taxa/16100419 Gastrotrichs in "EOL"]


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Look at other dictionaries:

  • gastrotrich — [gas′trō trik] n. [< ModL Gastrotricha < GASTRO + tricha, ciliate creatures < Gr neut. pl. of trichos, haired < thrix (gen. trichos), hair] any of a phylum (Gastrotricha) of minute, aquatic, wormlike animals that swim by means of… …   English World dictionary

  • gastrotrich — gastrotrichan /gas tro tri keuhn/, adj. /gas treuh trik/, n. any of the microscopic, multicellular animals of the class or phylum Gastrotricha, of fresh or salt waters, characterized by bands of cilia on the ventral surface of the bottle shaped… …   Universalium

  • gastrotrich — noun Etymology: ultimately from Greek gastr + trich , thrix hair more at trich Date: 1940 any of a phylum (Gastrotricha) of minute aquatic pseudocoelomate animals that usually have a spiny or scaly cuticle and cilia on the ventral surface …   New Collegiate Dictionary

  • gastrotrich — noun A microscopic aquatic animal of the phylum Gastrotricha, with a worm like body and cilia …   Wiktionary

  • gastrotrich — gas·tro·trich …   English syllables

  • gastrotrich — gas•tro•trich [[t]ˈgæs trə trɪk[/t]] n. ivt any tiny aquatic animal of the phylum Gastrotricha, having a long, sometimes bottle shaped body, with cilia on the underside • Etymology: 1935–40; < NL Gastrotricha < Gk gastro gastro + tricha,… …   From formal English to slang

  • gastrotrich — /ˈgæstrətrɪk/ (say gastruhtrik) noun one of the microscopic multicellular worms belonging to the phylum Gastrotricha, having bands of cilia on the ventral side of the body …   Australian English dictionary

  • gastrotrich — ˈgastrə.ˌtrik noun ( s) Etymology: New Latin Gastrotricha : an animal of the group Gastrotricha * * * gastrotrichan /gas tro tri keuhn/, adj. /gas treuh trik/, n. any of the microscopic, multicellular animals of the class or phylum Gastrotr …   Useful english dictionary

  • Heard Island and McDonald Islands — Heard Island Nickname: HIMI Satellite image of the southern tip of Heard Island. Cape Arkona is seen on the left side of the image, with Lied Glacier just above and Gotley Glacier just below. Big Ben Volcano and Mawson Peak are seen at the lower… …   Wikipedia

  • Benthos — are the organisms which live on, in, or near the seabed, also known as the benthic zone. [http://www.caml.aq/benthos/index.html Benthos] from the Census of Antarctic Marine Life website] They live in or near marine sedimentary environments, from… …   Wikipedia


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