Vertigo alpestris
Encyclopedia
Vertigo alpestris is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of minute, air-breathing land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s, terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod molluscs or micromollusk
Micromollusk
A micromollusk is a descriptive term for a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also reach adult size at very small...

s in the family Vertiginidae
Vertiginidae
Vertiginidae is a family of minute, air-breathing land snails, terrestrial pulmonate gastropod molluscs or micromollusks in the superfamily Pupilloidea.- Distribution :...

, the vertigo snails.

Shell description

The shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

 is subcylindrical, thin and semitransparent, closely and rather strongly striate in the line of growth. Its color is very glossy, a pale yellowish-horn-color. The periphery is rounded: epidermis thin. The shell has 4½ convex whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...

, but slightly compressed. The spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...

 is short, abrupt and bluntly pointed. The suture is excessively deep.

The shell aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....

 is semioval and subangular, owing to the outward compression of the periphery. The aperture has 4 teeth: one sharp and
prominent tooth on the middle of the pillar [parietal wall], one strong and also prominent and thick tooth on the pillar lip, and two lamellae or plate-like teeth which are placed at some little distance within the outer lip, but not on any rib or callous fold as in Vertigo pygmaea
Vertigo pygmaea
Vertigo pygmaea, common name the "crested vertigo", is a species of minute air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Vertiginidae.- Shell description :...

. The labial teeth are visible on the outside, owing to the thinness and transparency of the shell. The outer lip is rather thick and very slightly reflected, not strengthened by any rib either outside or inside. The outer edge is abruptly reflected. The inner lip is somewhat thickened in adult specimen. The umbilicus is small and narrow, but rather deep.

The width of the adult shell is 0.9-1.1 mm, the height is 1.6-2.15 mm.

Distribution

This species occurs in countries and islands including:

External links

  • distribution of Vertigo alpestris at European Environment Agency
    European Environment Agency
    European Environment Agency is an agency of the European Union. Its task is to provide sound, independent information on the environment. It is a major information source for those involved in developing, adopting, implementing and evaluating environmental policy, and also the general public...

    webpage
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