Difference between revisions of "Gastrotricha" - New World Encyclopedia

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The '''gastrotrichs''' (from [[Greek language|Greek]] ''gaster'' "stomach" and ''thrix'' "hair") are a phylum of microscopic (0.06-3.0 mm) [[animal]]s 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 [[symmetry (biology)#Bilateral symmetry|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 [[Gnathostomulid]]a, the [[Rotifer]]a, or the [[Nematode|Nematoda]]. On the other hand genetic studies place them as close relatives of the [[flatworm|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.
 
The '''gastrotrichs''' (from [[Greek language|Greek]] ''gaster'' "stomach" and ''thrix'' "hair") are a phylum of microscopic (0.06-3.0 mm) [[animal]]s 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 [[symmetry (biology)#Bilateral symmetry|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 [[Gnathostomulid]]a, the [[Rotifer]]a, or the [[Nematode|Nematoda]]. On the other hand genetic studies place them as close relatives of the [[flatworm|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.
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 +
==Classification==
 +
 +
See 88 for suborders, subfamilies, and subgenera
 +
 +
*'''Order Chaetonotida''' Remane, 1925
 +
**Family Chaetonotidae Gosse, 1864
 +
**:Genus Arenotus Kisielewski, 1987
 +
**:Genus Aspidiophorus Voigt, 1903
 +
**:Genus Caudichthydium Schwank, 1990
 +
**:Genus Chaetonotus Ehrenberg, 1830
 +
**:Genus Diuronotus Todaro, Balsamo & Kristensen, 2005
 +
**:Genus Fluxiderma d'Hondt, 1974
 +
**:Genus Ichthydium Ehrenberg, 1830
 +
**:Genus Halichaetonotus Remane, 1936
 +
**:Genus Heterolepidoderma Remane, 1926
 +
**:Genus Lepidochaetus Kisielewski 1991
 +
**:Genus Lepidodermella Blake, 1933
 +
**:Genus Musellifer Hummon, 1969
 +
**:Genus Polymerurus Remane, 1926
 +
**:Genus Rhomballichthys Schwank, 1990
 +
**:Genus Undula Kisielewski 1991
 +
**Family Dasydytidae Daday,1905
 +
**:Genus Anacanthoderma Marcolongo, 1910
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**:Genus Chitonodytes Remane, 1936
 +
**:Genus Dasydytes Gosse, 1851
 +
**:Genus Haltidytes Remane 1936
 +
**:Genus Ornamentula Kisielewski 1991
 +
**:Genus Setopus Grünspan, 1908
 +
**:Genus Stylochaeta Hlava, 1905
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**Family Dichaeturidae Remane, 1927
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**:Genus Dichaetura Lauterborn, 1913
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**Family Neodasyidae Remane, 1929
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**:Genus Neodasys Remane, 1927
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**Family Neogosseidae Remane, 1927
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**:Genus Neogossea Remane, 1927
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**:Genus Kijanebalola Beauchamp, 1932
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*Family  Proichthydidae Remane, 1927
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**:Genus Proichthydium Cordero, 1918
 +
**:Genus Proichthydioides Sudzuki, 1971
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**Family Xenotrichulidae Remane, 1927
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**:Genus Draculiciteria Hummon, 1974
 +
**:Genus Heteroxenotrichula Wilke, 1954
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**:Genus Xenotrichula Remane, 1927
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* '''Order Macrodasyida''' Remane, 1925
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**Family Dactylopdolidae Strand, 1929
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**:Genus Dactylopodola Strand, 1929
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**:Genus Dendrodasys Wilke, 1954
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**:Genus Dendropodola Hummon, Todaro & Tongiorgi, 1992
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**Family Lepidodasyidae Remane, 1927
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**:Genus Cephalodasys Remane, 1926
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**:Genus Dolichodasys Gagne, 1977
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**:Genus Lepidodasys Remane, 1926
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**:Genus Megadasys Schmidt, 1974
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**:Genus Mesodasys Remane, 1951
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**:Genus Paradasys Remane, 1934
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**:Genus Pleurodasys Remane, 1927
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**Family Macrodasyidae Remane, 1926
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**:Genus Macrodasys Remane, 1924
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**:Genus Urodasys Remane, 1926
 +
**Family Planodasyidae Rao & Clausen, 1970
 +
**:Genus Crasiella Clausen, 1968
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**:Genus Planodasys Rao & Clausen, 1970
 +
**Family Thaumastodermatidae Remane, 1927
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**:Genus Acanthodasys Remane, 1927
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**:Genus Diplodasys Remane, 1927
 +
**:Genus Hemidasys Claparède, 1867
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**:Genus Platydasys Remane, 1927
 +
**:Genus Pseudostomella Swedmark, 1956
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**:Genus Ptychostomella Remane, 1926
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**:Genus Tetranchyroderma Remane, 1926
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**:Genus Thaumastoderma Remane, 1926
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**Family Turbanellidae Remane, 1927
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**:Genus Desmodasys Clausen, 1965
 +
**:Genus Dinodasys Remane, 1927
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**:Genus Paraturbanella Remane, 1927
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**:Genus Prostobuccantia Evans & Hummon, 1991
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**:Genus Pseudoturbanella d'Hondt, 1968
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**:Genus Turbanella Schultze, 1853
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Family Xenodasyidae Todaro, Guidi, Leasi & Tongiorgi, 2006
 +
**:Genus Chordodasiopsis Todaro, Guidi, Leasi & Tongiorgi, 2006
 +
**:Genus Xenodasys Swedmark, 1967
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**Incertae Sedis
 +
**:Genus Marinellina Ruttner-Kolisko, 1955
 +
**:Genus Redudasys Kisielewski, 1987
 +
 +
  
 
==References==
 
==References==

Revision as of 22:06, 5 June 2008

Gastrotrichs
Darkfield photograph of a gastrotrich.
Darkfield photograph of a gastrotrich.
Scientific classification
Kingdom: Animalia
Subkingdom: Eumetazoa
(unranked) Bilateria
Superphylum: Platyzoa
Phylum: Gastrotricha
Metschnikoff, 1864
Orders

Macrodasyida
Chaetonotida

The gastrotrichs (from Greek gaster "stomach" and 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.

Classification

See 88 for suborders, subfamilies, and subgenera

  • Order Chaetonotida Remane, 1925
    • Family Chaetonotidae Gosse, 1864
      Genus Arenotus Kisielewski, 1987
      Genus Aspidiophorus Voigt, 1903
      Genus Caudichthydium Schwank, 1990
      Genus Chaetonotus Ehrenberg, 1830
      Genus Diuronotus Todaro, Balsamo & Kristensen, 2005
      Genus Fluxiderma d'Hondt, 1974
      Genus Ichthydium Ehrenberg, 1830
      Genus Halichaetonotus Remane, 1936
      Genus Heterolepidoderma Remane, 1926
      Genus Lepidochaetus Kisielewski 1991
      Genus Lepidodermella Blake, 1933
      Genus Musellifer Hummon, 1969
      Genus Polymerurus Remane, 1926
      Genus Rhomballichthys Schwank, 1990
      Genus Undula Kisielewski 1991
    • Family Dasydytidae Daday,1905
      Genus Anacanthoderma Marcolongo, 1910
      Genus Chitonodytes Remane, 1936
      Genus Dasydytes Gosse, 1851
      Genus Haltidytes Remane 1936
      Genus Ornamentula Kisielewski 1991
      Genus Setopus Grünspan, 1908
      Genus Stylochaeta Hlava, 1905
    • Family Dichaeturidae Remane, 1927
      Genus Dichaetura Lauterborn, 1913
    • Family Neodasyidae Remane, 1929
      Genus Neodasys Remane, 1927
    • Family Neogosseidae Remane, 1927
      Genus Neogossea Remane, 1927
      Genus Kijanebalola Beauchamp, 1932
  • Family Proichthydidae Remane, 1927
    • Genus Proichthydium Cordero, 1918
      Genus Proichthydioides Sudzuki, 1971
    • Family Xenotrichulidae Remane, 1927
      Genus Draculiciteria Hummon, 1974
      Genus Heteroxenotrichula Wilke, 1954
      Genus Xenotrichula Remane, 1927
  • Order Macrodasyida Remane, 1925
    • Family Dactylopdolidae Strand, 1929
      Genus Dactylopodola Strand, 1929
      Genus Dendrodasys Wilke, 1954
      Genus Dendropodola Hummon, Todaro & Tongiorgi, 1992
    • Family Lepidodasyidae Remane, 1927
      Genus Cephalodasys Remane, 1926
      Genus Dolichodasys Gagne, 1977
      Genus Lepidodasys Remane, 1926
      Genus Megadasys Schmidt, 1974
      Genus Mesodasys Remane, 1951
      Genus Paradasys Remane, 1934
      Genus Pleurodasys Remane, 1927
    • Family Macrodasyidae Remane, 1926
      Genus Macrodasys Remane, 1924
      Genus Urodasys Remane, 1926
    • Family Planodasyidae Rao & Clausen, 1970
      Genus Crasiella Clausen, 1968
      Genus Planodasys Rao & Clausen, 1970
    • Family Thaumastodermatidae Remane, 1927
      Genus Acanthodasys Remane, 1927
      Genus Diplodasys Remane, 1927
      Genus Hemidasys Claparède, 1867
      Genus Platydasys Remane, 1927
      Genus Pseudostomella Swedmark, 1956
      Genus Ptychostomella Remane, 1926
      Genus Tetranchyroderma Remane, 1926
      Genus Thaumastoderma Remane, 1926
    • Family Turbanellidae Remane, 1927
      Genus Desmodasys Clausen, 1965
      Genus Dinodasys Remane, 1927
      Genus Paraturbanella Remane, 1927
      Genus Prostobuccantia Evans & Hummon, 1991
      Genus Pseudoturbanella d'Hondt, 1968
      Genus Turbanella Schultze, 1853

Family Xenodasyidae Todaro, Guidi, Leasi & Tongiorgi, 2006

    • Genus Chordodasiopsis Todaro, Guidi, Leasi & Tongiorgi, 2006
      Genus Xenodasys Swedmark, 1967
    • Incertae Sedis
      Genus Marinellina Ruttner-Kolisko, 1955
      Genus Redudasys Kisielewski, 1987


References
ISBN links support NWE through referral fees

  • Integrated Taxonomic Information System (ITIS). 2006b. Chaetonotida Remane, 1924 ITIS Taxonomic Serial No.: 57822. Retrieved June 5, 2008.
  • Integrated Taxonomic Information System (ITIS). 2006c. Macrodasyida Remane, 1924 ITIS Taxonomic Serial No.: 57598. Retrieved June 5, 2008.


External links

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