Umbrella jellyfish
| Umbrella jellyfish | ||||||||||||
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Chrysaora sp. |
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| Scientific name | ||||||||||||
| Scyphozoa | ||||||||||||
| Goette , 1887 | ||||||||||||
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Umbrella jellyfish or disc jellyfish (Scyphozoa) are a class of cnidarians (Cnidaria). They are also known as real jellyfish . The umbrella jellyfish form three orders: Crown jellyfish (Coronatae), flag jellyfish (Semaeostomae) and root-mouth jellyfish (Rhizostomeae). About 130 species belong to the Scyphozoa. The mostly solitary animals are characterized by large medusa and small polyps . Reproduction takes place alternately asexually, by pinching off ephyral larvae from the sessile polyp ( strobilation ), and sexually (a so-called metagenesis ).
features
Umbrella jellyfish are transparent animals made of a thick gelatinous mass with tentacles emerging from the edge of the umbrella . This is also where light and tactile organs sit, the ropes . The umbrella jellyfish have swimming bells. The tentacles can be up to 30 m long, on them are the poisonous nettle capsules . A jellyfish's body is 98% water. Some umbrella jellyfish are only a few millimeters in size, but some can be up to 2 m in diameter.
Most of the coastal forms in their larval stage form a "scyphopolyp" with exactly four gastric chambers. It transforms asexually into a pile of tiny medusa larvae, a process known as strobilation. The Medus larva is also called "Ephyra" and after a while in the plankton it turns into a jellyfish.
Occurrence
Most jellyfish species are restricted to the coastal area because they depend on a suitable substrate for their reproduction during the polyp generation in a sedentary way of life. But there are also deep sea jellyfish that multiply in the open sea and do not form a generation of polyps.
Types (selection)
- Ear jellyfish ( Aurelia aurita )
- Cassiopea andromeda
- Compass jellyfish ( Chrysaora hysoscella )
- Fried egg jellyfish ( Cotylorhiza tuberculata )
- Mastigias papua (e.g. in the jellyfish lake of Palau)
- Nomura jellyfish ( Nemopilema nomurai )
- Crowned jellyfish ( Periphylla periphylla )
- Dotted root mouth jellyfish ( Phyllorhiza punctata )
- Root mouth jellyfish ( Rhizostoma octopus )
- Rhopilema esculentum
- Rhopilema verrilli
- Stomolophus meleagris
- Stomolophus nomurai
literature
- Neil A. Campbell: Biology. 6th edition Spektrum, Heidelberg 1997, ISBN 3-8274-0032-5
- Ernst Horstmann: Investigations on the physiology of the swimming movements of the Scyphomeduses Aurelia aurita and Cyanea capillata , in Pflüger's archive for the entire physiology of humans and animals . Volume 234, Issue 4, ISSN 0031-6768 , Würzburg 1934, DNB 570715172 (Dissertation University of Kiel 1934, 28 pages, with illustrations).
