Limnognathia

Limnognathia
Limnognathia
Scientific classification e
Kingdom: Animalia
(unranked): Platyzoa
Phylum: Gnathifera
Class: Micrognathozoa
Order: Limnognathida
Family: Limnognathiidae
Genus: Limnognathia
Species: L. maerski
Binomial name
Limnognathia maerski
Kristensen & Funch, 2000

Limnognathia maerski is a microscopic animal, discovered living in homothermic springs on Disko Island, Greenland in 1994, that has variously been assigned as a class or subphylum in the phylum Gnathifera or as a phylum in a Gnathifera superphylum, named Micrognathozoa. It is related to the rotifers and gnathostomulids, grouped together as the Gnathifera.[1][2] With an average length of one-tenth of a millimetre, it is one of the smallest animals known.

L. maerski has very complicated jaws, with fifteen separate elements. The parts of the jaw structure are connected by ligaments and muscles. The jaw parts are very small, ranging from 4 μm to 14 μm. The animal can extend part of its jaw structure outside of its mouth while eating. It also extends much of its jaw structure outside of its mouth when it is regurgitating items that are indigestible.

L. maerski has a large ganglion, or 'brain', in its head, and paired nerve cords extending ventrally (along the lower side of the body) towards the tail. Stiff sensory bristles made up of one to three cilia are scattered about the body. These bristles are similar to ones found on gnathostomulids, but up to three cilia may arise from a single cell in L. maerski, while gnathostomulids never have more than one cilium per cell.

Flexible cilia are arranged in a horseshoe-shaped area on the forehead, and in spots on the sides of the head and in two rows on the underside of the body. The cilia on the forehead create a current that moves food particles towards the mouth. The other cilia move the animal.

All specimens of L. maerski that have been collected have had female organs. They lay two kinds of eggs: thin-walled eggs that hatch quickly, and thick-walled eggs that are believed to be resistant to freezing, and thus capable of over-wintering and hatching in the spring. The same pattern is known from rotifers, where thick-walled eggs only form after fertilization by males. The youngest L. maerski specimens collected may also have male organs, and it is now theorized that the animals hatch as males and then become females.

Phylogeny

Cladogram (adapted from [1]) showing the relationships of Limnognathia:

Gnathifera

Gnathostomulida




Micrognathozoa




Acanthocephala



Rotifera





References


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Look at other dictionaries:

  • Limnognathia — maerski Systematik Stamm: Micrognathozoa Klasse: nicht eingeteilt Ordnung: nicht eingeteilt Familie: nicht eingeteilt …   Deutsch Wikipedia

  • Limnognathia — maerski animal microscópico descubierto en Groenlandia en 2000, que se cree que pertenece a su propio phylum, Micrognathozoa. Los ejemplares que se encontraron se trasladaron al Museo de Zoología de Copenhague. Estaría cercano a los rotíferos y… …   Enciclopedia Universal

  • Limnognathia — Micrognathozoa Micrognathozoa …   Wikipédia en Français

  • Limnognathia maerski — Systematik Stamm: Micrognathozoa Klasse: nicht eingeteilt …   Deutsch Wikipedia

  • Limnognathia maerski — Научная классификация …   Википедия

  • Micrognathozoa — Limnognathia maerski Systematik Stamm: Micrognathozoa Klasse: nicht eingeteilt Ordnung: nicht eingeteilt Familie: nicht eingeteilt …   Deutsch Wikipedia

  • Micrognathozoa —   Limnognathia Clasificación científica Reino: Animalia …   Wikipedia Español

  • Micrognathozoa — Micrognathozoa …   Wikipédia en Français

  • Disko Island — Disko Native name: Qeqertarsuaq Qeqertarsuaq town on Disko Island …   Wikipedia

  • Gnathifera — ist ein in der Systematik bei Wikipedia nicht verwendetes Superphylum, unter dem man oft die Phyla Gnathostomulida, Micrognathozoa, Rotifera und Acanthocephala zusammenfasst, seltener auch die Chaetognatha. Bezeichnendes und namensgebendes… …   Deutsch Wikipedia

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