Jaw mouth

Jaw mouth
Gnathostomula paradoxa ,
Systematics
without rank: Multicellular animals (Metazoa) without rank: Bilateria without rank: Primordial mouths (protostomia) Trunk : Jaw mouth
Scientific name
Gnathostomulida
Ax , 1956
Orders
Filospermoidea Bursovaginoidea

The jaw mouths (Gnathostomulida) are small, one to four millimeters long marine worms that are counted among the meiofauna . The 91 species live mainly in sands with a high proportion of sulphides and organic matter. All species are hermaphrodites. The first specimens were discovered by Adolf Remane in 1928 .

It is named after the pair of jaws at the front end of the animals. The ectoderm consists of monociliary cells, which means that each individual cell has only one cilia. These monciliar cells already appeared in the "subdivision" of the Bilateria and are still preserved in the Gnathostomulida, in contrast to the flatworms (platelets). With the stroke of the cilia, they move both forwards and backwards.

The protonephridia are modified : here several organs are lined up in the body. In each individual organ, only the terminal cell has a cilium.

The mouths of the jaws are not found fossilized . Because of the similar jaw apparatus and the protonephridia, one assumes a relationship with the rotifers (Rotatoria) and the abdominal corsets (Gastrotricha).

Systematics

The system of the jaw mouths is based on a work by the Austrian marine biologist Wolfgang Sterrer , the former director of the Bermuda Biological Station , from 1972.

• Order Bursovaginoidea Sterrer, 1972
  • Suborder Conophoralia Sterrer, 1972
    • Austrognathiidae Sterrer family , 1972
      • Austrognatharia Sterrer, 1971
      • Austrognathia Sterrer, 1965
      • Triplignathia Sterrer, 1991
  • Suborder Scleroperalia Sterrer, 1972
    • Family Agnathiellidae Sterrer, 1972
      • Agnathiella Sterrer, 1971
      • Paragnathiella Sterrer, 1997
    • Family Clausognathiidae Sterrer, 1972
      • Clausognathia Sterrer, 1992
    • Family Gnathostomariidae Sterrer, 1972
      • Gnathostomaria Ax, 1956
    • Family Gnathostomulidae Sterrer, 1972
      • Corculognathia Ehlers & Ehlers, 1973
      • Gnathostomula Ax, 1956
      • Ratugnathia Sterrer, 1991
      • Semaeognathia Riedl 1970
    • Family Mesognathariidae Sterrer, 1972
      • Labidognathia Riedl 1970
      • Mesognatharia Sterrer, 1966
      • Tenuignathia Sterrer, 1976
    • Family Onychognathiidae Sterrer, 1972
      • Goannagnathia Sterrer, 2001
      • Nanognathia Sterrer, 1972
      • Onychognathia Riedl, 1971
      • Valvognathia Kristensen & Norrevang, 1978
      • Vampyrognathia Sterrer, 1998
    • Family Paucidentulidae Sterrer, 1972
      • Paucidentula Sterrer, 1998
    • Problognathiidae family Sterrer & Farris, 1975
      • Problognathia Sterrer & Farris, 1975
    • Rastrognathiidae family Kristensen & Norrevang, 1977
      • Rastrognathia Kristensen & Norrevang, 1977

• Order Filospermoidea Sterrer, 1972
  • • Family Haplognathiidae Sterrer, 1972
      • Haplognathia Sterrer, 1970
    • Family Pterognathiidae Sterrer, 1972
      • Cosmognathia Sterrer, 1991
      • Pterognathia Sterrer, 1966

literature

• Peter Ax : The Gnathostomulida, a mysterious group of worms from the sea sand. In: Treatises of the Academy of Sciences and Literature Mainz, mathematical and natural science class. 8, 1956, pp. 1-32.
• Peter Ax: The position of the Gnathostomulida and Platyhelminthes in the phylogenetic system of the Bilateria. In: S. Conway Morris, JD George, R. Gibson, HM Platt (Eds.): The Origins and Relationships of Lower Invertebrates. Clarendon Press, Oxford 1986, pp. 168-180.
• Rupert J. Riedl : Gnathostomulida from America. In: Science. 163, 1969, pp. 445-442.
• K. Rützler, IG Macintyre (Ed.): The Atlantic Barrier Reef Ecosystem at Carrie Bow Cay, Belize. Volume 1: Structure and Communities. Smithsonian Institution Press, Washington, DC 1982, OCLC 615548968 .
• Wolfgang Sterrer : Gnathostomulida: Problems and procedures. In: Smithsonian Contributions to Zoology. 76, 1971, pp. 9-15.
• Wolfgang Sterrer: Systematics and evolution within the Gnathostomulida. In: Systematic Zoology. 21 (2), 1972, pp. 151-173.
• Volker Storch, Ulrich Welsch: Systematic Zoology. 6th edition. Spectrum Academic Publishing House, 2003, ISBN 3-8274-1112-2 .

Web links

• Integrated Taxonomic Information System Gnathostomulida Sterrer, 1972