Big river clam
| Big river clam | ||||||||||||
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Unio tumidus |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Unio tumidus | ||||||||||||
| Philipsson , 1788 |
The Great River mussel , also Inflated river mussel ( Unio tumidus ) is one of the great freshwater - shells , which applies in Germany of the early 21st century as endangered species.
features
The shell of the mussel is bean- or kidney-shaped and is usually 8 to 10 centimeters long, in rare exceptions also up to 12 centimeters. The skin is usually brownish or black and often encrusted with lime or a black iron - manganese coating. The soft body of the river mussel is light-colored and the rear part has a large inflow opening and a smooth-edged outflow opening above it. The front part of the housing is dug in by the shell so that only the inflow and outflow openings protrude from the rear. It has a foot for locomotion, which it can stretch out on the underside between the flaps for locomotion. The great river mussel can get very old. Individual specimens reach an age of over 50 years.
Way of life, occurrence and distribution
It lives in lakes as well as in slow-flowing rivers on sandy grounds. However, lakes are preferred, where they often live in the riparian zone influenced by the impact of waves. It goes down to several meters of water. Known larger populations only exist in the relatively clean lakes in northern Germany due to the heavy river water pollution caused by industry. There are larger occurrences in Schleswig-Holstein in the eastern hill country and in Mecklenburg-Western Pomerania (e.g. in the Feldberg lake landscape ). Here were z. Sometimes high population densities with up to 70 individuals per m² were observed. The (original) distribution area of the great river mussel extends in Europe from eastern France and western Switzerland through central Europe to northern Scandinavia ( Arctic Circle ) and in the east to the Ural Mountains, in the Danube it occurs from Vienna.
Individual evidence
- ↑ Zettler et al., P. 233
literature
- Rosina Fechter and Gerhard Falkner: molluscs. 287 pp., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10), ISBN 3-570-03414-3
- Michael L. Zettler et al .: The land and freshwater mollusks of Mecklenburg-Western Pomerania. 318 p., Obotrite pressure, Schwerin 2006, ISBN 3-933781-52-3
Web link
- Unio tumidus inthe IUCN Red List of Threatened Species 2013.1. Posted by: Van Damme, D., 2011. Retrieved November 22, 2013.