Vertigo heldi
Lean whorl snail ( Vertigo Heldi )
The Lean whorl snail ( Vertigo Heldi ) is a species of snail from the family of the diaper snails ( Vertiginidae ) in the subordination of terrestrial snails ( gastropod ).
- 5.1 Literature
- 5.2 Notes and references
Features
The right-handed cylindrical housing of lean whorl snail is 2.5 to 2.7 mm high and 1.2 mm wide (after Clessin 4.0 to 4.5 mm high, 1 mm wide). It has 5.5 to 6 curved turns which are offset from each other by a deep weld. The last three turns to take hardly in diameter. The final turn is under the seam edge, or "shoulder" from. The case is brown and translucent with a glossy finish; this is very finely striated. The mouth edge is hardly thickened and therefore appears relatively sharp. At the top of only a weak neck ridge is formed. Also the teeth, a palatal and parietal are only weakly developed, sometimes even missing. Inside, the callus weak.
Similar Species
The species is difficult to distinguish from some extreme forms of very variable Commons whorl snail ( Vertigo pygmaea ). In general, the case of lean whorl snail is but bigger, something more cylindrical and therefore narrower than the enclosure of the commons whorl snail. Fresh housing are more translucent and the surface shines stronger.
Geographical distribution and habitat
The range of the species is restricted to southern Germany, northern Switzerland and Austria. In Switzerland, it occurs at 300 to 400 meters above sea level. It is very rare and the deposits are very scattered. She lives there in marshy meadows and wet grasslands, mainly in the hill country.
Taxonomy
The taxon was described in 1877 by Stephan Clessin as Pupa ( Vertigo ) Heldi first time. Some authors subdivide the genus into two subgenera Vertigo: Vertigo ( Vertigo ) OF Müller, 1773 and Vertigo ( Vertilla ) Moquin - Tandon, 1856. During this subgenus outline the slender whorl snail is in the genus Vertigo ( Vertigo ) provided.
Endangering
In Germany the species is threatened with extinction ( hazard category 1).