Desmoulin's whorl snail
Desmoulins' whorl snail ( Vertigo moulinsiana ) ( Scale in millimeters )
The Desmoulins' whorl snail ( Vertigo moulinsiana ) is a species of snail from the family of the diaper snails ( Vertiginidae ) that are expected to the subordination of terrestrial snails ( gastropod ). She prefers to live in the swampy area silting of stagnant water, particularly in the execution sedge (eg Sumpfsegge, Ufersegge or Rispensegge ). The soil typical locations is characterized by abundance of nutrients and near-surface water, and must not be too little calcium.
Features
The housing has a length of only 2.2 to 2.7 mm and in width from 1.3 to 1.6 mm. It is bulbous ovoid. The mouth has four projections ( so-called "teeth" ), which may sometimes have additional, smaller teeth at the base. They should prevent predators (eg predatory insect larvae ) and parasites from entering the housing and prevent the too rapid drying out of the body. Foot and head of the bulbous whorl snail are glossy black. The color of the body ranges from reddish brown to pale yellowish; the surface is shiny. The housings are almost smooth, only a weak Anwachsstreifung can be seen.
Dissemination
There are isolated occurrences of this kind in Central and Western Europe, the British Isles and the southern parts of Scandinavia. The North African coast is the southernmost region where up to now a colony of this species of snail was discovered. The largest colonies with an intact population are located in the southeast of England, Ireland and in North East Germany. In the east, the occurrence extends to the Caucasus. The species is relatively sensitive to low winter temperatures. The isolated occurrence in Central Europe are therefore considered relics of the post-glacial warm period ( Atlantic period, up to 3800 around 7200 BC) interpreted. However, this is controversial.
Behavior
The bulbous whorl snail is a nocturnal animal. During the day it rests with her mucus stuck to the leaves larger sedges. It is a typical grazers, their diet consists of fungi that live on these grasses, as well as pollen and other plant particles. The Desmoulins' whorl snail is still poorly understood. Due to their small size, it has to rely mainly on passive dispersal by waterfowl. So adhering eggs or hatchlings are transported over several kilometers into new, suitable habitats on the plumage. A spread by wind, similar to pollen, however, is not in question, since the Desmoulins' whorl snail can not produce the necessary for such a costly way egg masses. The Desmoulins' whorl snail multiplies as mutually fertilizing hermaphrodite, but it can also fertilize themselves. From May to August, it drops a small number weichschaliger eggs. As the animals survive the winter, is not yet fully understood. They were discovered sitting both at ground level between organic material and leaves as well as free on the leaf undersides of large sedge. Hard winters decimate the populations significantly.
Endangering
The Desmoulins' whorl snail is threatened throughout its area of distribution of extinction. Above all, the destruction of their habitat is endangered and in some European countries already extinct (Netherlands? ). In Germany it is on the "Red List" and is considered to be at high risk.
System
For this type exist a whole series of synonyms such as Pupa charpentieri Shuttleworth, 1852 Pupa laevigata v. gallstone, 1852, Vertigo limbata Partiot, 1855, Vertigo Ventrosa Heyne man, 1862 Pupa kuesteriana Westerlund, 1875 as well as some misspellings Pupa desmoulinsiana Jeffreys, 1855, Vertigo Moquin - Tandon moulinsii, 1855 and Vertigo demoulinsi Germain, 1913.
Others
In June 2002 pieces a stamp was designed whorl snail with a picture of bulbous and printed by the Federal Post Office under the motto " Endangered Animals " by Leon Berger graphic artist Günter Jacki. The snail was collected from the Stuttgart Natural History Museum in Goldersbach at Tübingen under the Habitats Directive in 1999. In 2003 she was elected to the soft animal of the year.