Copelata
| Copelata | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the class | ||||||||||||
| Larvacea | ||||||||||||
| Fol , 1874 | ||||||||||||
| Scientific name of the order | ||||||||||||
| Copelata | ||||||||||||
The Copelata are the only order of the Larvacea , a class of tunicates (Urochordata). After a name for the class that is now considered a synonym , Appendicularia, the animals are also called Appendikularien in German . However, this name can lead to confusion with a subordinate genus. The order includes 64 species in three families, all of which live in the sea as filter feeders .
features
Larvacea are transparent, small living things; the outer skin, the coat, which is common in tunicates , is missing. Even after they have reached sexual maturity, the animals retain the tadpole-like larva body. The body reaches between 1 ( oikopleura ) and 25 ( bathochordaeus ) millimeters in length and consists of a trunk containing most of the internal organs and a tail, in the middle of which the notochord runs.
From the trunk the animals secrete their casing from a slimy substance, which can reach a diameter of 4 millimeters ( oikopleura ) to 2 centimeters ( bathochordaeus ). The housing can enclose the animals completely, as in the genera Oikopleura and Bathochordaeus , or only include the tail, as in the Fritillaria . It is constructed as a complex slimy network, it is used to collect plankton . The body and casing are of a gelatinous consistency.
Way of life
Larvacea live as filter feeders worldwide in pelagic ocean currents . The regular beating of the tail creates a flow of water through the housing, with which food is swirled in, a complex filter system serves to separate nutrients.
In the event of disturbances, the animals leave their housing through an opening in the rear area and soon form a new housing from existing approaches on the trunk. The animals are food for numerous animals, including anchovies . Some species have bioluminescent granules embedded in the housing that are believed to protect the animal in the event of an attack by leaving it empty and glowing while the actual body sinks and a new housing is built.
Larvacea reproduce exclusively sexually, with the exception of Oikopleura dioica they are hermaphroditic. The sperm are released directly into the surrounding water, the eggs are released by tearing the body wall, which causes the animal to perish. With a good nutritional basis, the production of gametes can accelerate extremely and lead to real "blooms" within a few days.
Systematics
The order contains three families and 64 species.
- Fritillariidae
- Kowalevskiidae
- Oikopleuridae
proof
- ↑ a b c d e Michael S. Schaadt: Appendicularia (Larvaceans) . In: Michael Hutchins, Dennis A. Thoney, Neil Schlager (Eds.): Grzimek's Animal Life Encyclopedia. Second edition. Volume 1: Lower Metazoans and Lesser Deuterostomes , 2003, pp. 473-477, ISBN 0787653624
- ^ WoRMS (2009): Copelata World Register of Marine Species
