Cycliophora

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Cycliophora
Systematics
without rank: Multicellular animals (Metazoa)
without rank: Bilateria
without rank: Primordial mouths (protostomia)
Trunk : Cycliophora
Scientific name
Cycliophora
Kristensen & Funch , 1995

Cycliophora ( Gr .: Kreistragende) is a new strain of multicellular animals introduced in 1995 by the Danish biologists Reinhardt Kristensen and Peter Funch . Currently only the two species Symbion pandora and Symbion americanus ( Obst et al. 2006) are known, which live on the mouthparts of lobsters and only grow to around 350 µm .

features

The so far known species of Cycliophora in their sessile and best-known form reach a body length of about 350 micrometers. They are attached to the mouthparts of the lobsters on which they live with the help of a suction cup-like footplate and a stem. Nutrition takes place by swirling in food particles through a cilia ring around the mouth opening. The anus is located as a separate exit near the mouth opening. New buds are continually emerging in the animal's body, replacing the nutritional apparatus and forming asexual larvae.

Reproduction

Cycliophora can reproduce both sexually and asexually. They have three different stages of development, which are largely free-swimming. These can be divided into larvae that can develop a finished sessile animal, dwarf males with a typical length of around 84 micrometers, and female animals that attach themselves to the lobster mouthparts and can release new larvae. None of the free-swimming stages are feeding.

The sexual reproduction of the Cycliophora is closely linked to the molting of the lobster. At the end of its molting process, sexually mature Cycliophora are found on the mouthparts.

Systematics

The exact position of the Cycliophora within the phylogenetic system of animals has not been conclusively clarified and is accordingly controversial. They are placed in different parts of the system by different scientists. Some assume a relationship with flatworms . Others see a closer relationship with the bryozoa , which they resemble in their sessile way of life and reproduction. The cupworms (Kamptozoa) are also mentioned as a possible sister group due to their morphological and molecular characteristics .

species

So far, only two species are known from the taxon Cycliophora, both of which live on the mouthparts of lobsters:

Another, previously unnamed species was also discovered on the European lobster ( Homarus gammarus ).

literature

  1. ^ P. Funch, RM Kristensen: Cycliophora is a new phylum with affinities to Entoprocta and Ectoprocta. Nature 378, 1995: pages 711-714
  2. ↑ M. Obst, P. Funch, RM Kristensen: A new species of Cycliophora from the mouthparts of the American lobster Homarus americanus (Nephropidae, Decapoda). Organisms, Diversity & Evolution, 6 (2), 2006
  3. ^ KM Halanych: The new view of animal phylogeny. Annual Review of Ecology, Evolution, and Systematics 35, 2004; Pages 229-256.
  4. ↑ Torsten H. Struck, Alexandra R. Wey-Fabrizius, Anja Golombek, Lars Hering, Anne Weigert, Christoph Bleidorn, Sabrina Klebow, Nataliia Iakovenko, Bernhard Hausdorf, Malte Petersen, Patrick Kück, Holger Herlyn, Thomas Hankel (2014): Platyzoan Paraphyly Based on Phylogenomic Data Supports a Noncoelomate Ancestry of Spiralia. Molecular Biology and Evolution 31 (7): 1833-1849. doi : 10.1093 / molbev / msu143
  5. ↑ Jessica M. Baker, Gonzalo Giribet: A molecular phylogenetic approach to the phylum Cycliophora provides further evidence for cryptic speciation in Symbion americanus. Zoologica Scripta 36, ​​July 2007, pages 353-359. doi : 10.1111 / j.1463-6409.2006.00288.x

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