Palaeacanthocephala
| Palaeacanthocephala | ||||||||||||
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Pomphorhynchus in the rectum of a blue fish ( Pomatomus saltatrix ) |
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| Scientific name | ||||||||||||
| Palaeacanthocephala | ||||||||||||
| Meyer , 1931 | ||||||||||||
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The Palaeacanthocephala are a class of scratchworms with an obligatory host change , which parasitize as adult intestinal parasites in various vertebrate groups such as fish, amphibians, birds and mammals and usually have aquatic life cycles. They are small to medium-sized species with an average length of a few centimeters.
features
As anatomical features, the main canals of the lacunae system in the Palaeacanthocephala are located on the side of the body and not, as in the Archiacanthocephala, dorsally and ventrally. Protonephridia are absent.
The males have two to eight cement glands and only a few cell nuclei in the syncitial ligament . In the females there is only one ligament sac, which resulted from a fusion of the originally two sacs. With sexual maturity, the walls of the sac dissolve and the eggs are placed in the body cavity, where they float freely.
Way of life
The Palaeacanthocephala mostly have an aquatic life cycle. The final hosts are mainly fish, but amphibians, water birds or seals are also possible hosts. The animals primarily use small crustaceans such as various flea crabs or water isopods as intermediate hosts .
Systematics
In the following, the orders and families of the Palaeacanthocephala, as well as some selected genera are listed:
supporting documents
Evidence cited
Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:
- ↑ http://parasitology.informatik.uni-wuerzburg.de/login/n/h/0008.html ( Memento from February 13, 2009 in the Internet Archive )
literature
- Sievert Lorenzen: Acanthocephala, scratches. In: Wilfried Westheide , Reinhard Rieger: Special Zoology. Part 1: Protozoa and invertebrates. Gustav Fischer Verlag, Stuttgart and Jena 1996, ISBN 3-437-20515-3 , pp. 723-728.
- Article Acanthocephala in: Heinz Mehlhorn: Encyclopedic Reference of Parasitology. Biology, Structure, Function Springer Verlag, Berlin, Heidelberg, New York 2001; Pages 3-27. ISBN 3-540-66239-1
