White-mouthed pan snail
White-mouthed pan snail | ||||||||||||
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![]() White-mouthed pan snail |
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Anisus leucostoma | ||||||||||||
( Millet , 1813) |
The anisus leucostoma ( anisus leucostoma ) is a basommatophora (Basommatophora) from the family of planorbidae (Planorbidae).
features
The case measure about 6 to 9 mm in diameter. They are flat, disc-shaped and only about 1.5 mm high. The top is almost flat, the bottom is slightly sunk. About 6 to 6.5 turns are formed, which increase evenly. The whorls are convexly rounded, slightly canted in the inner third on the underside.
Reproduction
The animals become sexually mature after about 3 to 6 months and then lay several spawning balls containing 2 to 8 eggs. The development time is strongly dependent on temperature and takes about 11 days at 18 °.
Way of life, occurrence and distribution
The species lives in small and tiny stagnant bodies of water that can occasionally dry out. If the water dries up, the animals close the mouth of the housing with a parchment-like lid. They endure strong summer heat as well as strong winter frosts down to below -20 °. The animals grate the surface of plants rotting in the water; they probably also eat detritus. The species is widespread in Europe to western Asia.
Similar species
The species differs from Anisus spirorbis by the more evenly increasing whorls; significantly more whorls are formed. On the other hand, anisus calculiformis has one or two whorls more.
Danger
The species is on the “Red Lists” of endangered species in Switzerland. It is classified there as "vulnerable" (= endangered).
Systematics
The genus Anisus is divided into two sub-genera by some of the authors: Anisus (Anisus) Studer, 1820 and Anisus (Disculifer) C. Boettger, 1944. In this sub-genre, Anisus leucostoma is placed in the nominate sub-genus Anisus .
literature
- Rosina Fechter and Gerhard Falkner: molluscs. Mosaik-Verlag (Steinbach's Nature Guide 10), Munich 1990, ISBN 3-570-03414-3 , p. 287.
- Ewald Frömming: Biology of the Central European freshwater snails. Duncker & Humblot, Berlin 1956. p. 313.
- Peter Glöer: The animal world of Germany. Mollusca I Freshwater gastropods of Northern and Central Europe Key to identification, way of life, distribution. 2. rework. Edition, 327 D., ConchBooks, Hackenheim 2002, ISBN 3-925919-60-0 .
Web links
- Fauna Europaea
- MollBase - Distribution Atlas Schleswig-Holstein 1991
- AnimalBase
- Anisus leucostoma inthe IUCN 2013 Red List of Threatened Species . Posted by: Van Damme, D. & Seddon, MB, 2011. Retrieved February 13, 2014.