Vertigo arctica 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...

, a 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 mollusk 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 :...

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Distribution

• Poland - critically endangered
  Critically endangered
  Version 2010.3 of the IUCN Red List of Threatened Species identified 3744 Critically Endangered species, subspecies and varieties, stocks and subpopulations.Critically Endangered by kingdom:*1993 Animalia*2 Fungi*1745 Plantae*4 Protista-References:...
  
  

Shell description

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 dextral, rimate, ovate, thin, smoothish, somewhat glossy, pellucid, brownish-tawny. The shell has 5 to 5 ½ 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...

, convex, the last nearly two-fifths the altitude, rounded at base, anteriorly having a somewhat swollen crest.

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 slightly oblique, semiovate or piriform, obstructed by 3 teeth: in the middle of the parietal wall, on the columella, and a smaller one in the palate (frequently wanting). Peristome is spreading, slightly labiate, the margins joined by a callus, the right margin very strongly curved above, columellar margin is somewhat dilated, spreading.

The width of the adult shell varies is 2.5 mm, the height from 1.5 mm.