Vertigo modesta
Vertigo modesta, holotype ( from Say in Keating, 1824: Taf.15 Fig. 5)
The Arctic whorl snail ( Vertigo modesta ) is a species of snail of the family of the diaper snails ( Vertiginidae ) from the subordination of terrestrial snails ( gastropod ). Most likely it is in this zirkumpolararktischen and alpine taxon to a Artkomplex.
- 5.1 Literature
- 5.2 Notes and references
Features
The right-handed, oblong- cylindrical to egg-shaped housing is approximately 2.05 to 2.6 mm in height and 1.25 to 1.55 mm wide. It has 5 ( to 6) strongly curved, rapidly increasing turns and a deep seam. The apex is bluntly rounded. The Protokonch is granulated white and fine. The surface of the convolutions has many fine and regular growth lines. In the middle turns the Anwachsstreifung is somewhat clearer. The casing is light yellowish - brown, the surface has a silky. The last turn takes up more than half of the total height. The mouth is in the front view heart shaped wrong. The aperture rim is simple, hardly thickened and hardly expanded. The reinforcement of the estuary consists of 0-5 small teeth, usually four or three teeth are formed, a parietal tooth, a tooth columellarer and a deep-seated palatal tooth. This may also be omitted, also, in addition in the upper palatal another small tooth be formed. Rarely is also a angularis available ( in North American forms). Most lack a neck ridge. No or only a very small callus Callus is usually formed inside the mouth.
Similar Species
The case of the Nordic whorl snail is similar to the Arctic whorl snail. In the latter type of Apex runs into something more pointed. The turns take slightly faster and are more curved.
Geographical distribution and habitat
The Artkomplex the Arctic whorl snail has a circumpolar arctic distribution, in Europe and in the Alps, the Carpathians, the Pyrenees and Scotland. The Subspecies hoppei even occurs in Greenland.
The animals are found in damp, shady locations of mountain valleys. In Scandinavia, they typically occur on valley slopes, which are covered with subarctic forest. They live under rocks or overgrown plants boulder fields and in the leaf litter. In the Alps, they are found mainly at altitudes above 1,600 meters to about 2,100 meters above sea level.
Taxonomy
The Tayon was described in 1824 by Thomas Say in Hypolitus William Keating's "Narrative of an expedition to the source of St. Peter 's River, Lake Winnepeek, Lake of the Woods, & c" as Pupa modesta first time.
Subspecies according to Pilsbry, Welter Schultes and " Molluscs of central Europe"
- Vertigo modesta modesta (Say, 1824), Nominatunterart, North America, 4 teeth, parietal, columellarer and lower palatal tooth same size, upper palatal tooth smaller
- Vertigo modesta arctica ( Wallenberg, 1868), Europe, West Siberia, parietal and columellarer tooth present, palatal teeth present or absent
- Vertigo modesta corpulenta ( Morse, 1865), Nevada, 4 teeth, parietal, columellarer tooth, two palatal teeth, housing thicker
- Vertigo modesta hoppei Möller, 1842, Greenland, Arctic Canada, Alaska, 0-3 teeth
- Vertigo modesta insculpta Pilsbry, 1919, Arizona, New Mexico, about 3000 m, strong Anwachsstreifung on vorvorletzter and penultimate, occasionally even on the last turn
- Vertigo modesta krauseana Reinhardt, 1883, Eastern Siberia, Kuril Islands, Kamchatka, a parietal tooth ( and it may be the trace of a tooth columellaren be present).
- Vertigo modesta Tirolensis Gredler, 1869, a columellarer tooth, a parietal tooth
- Vertigo modesta ultima Pilsbry, 1919, Alaska, no teeth
- Vertigo modesta castanea Sterki, 1892, California, 2700 m altitude, all the teeth very small, if any, lower palatal tooth relatively large, columellarer tooth usually present, parietal tooth is very small or absent, upper palatal tooth very small or absent
- Vertigo modesta sculptilis Pilsbry, 1934, strong Anwachsstreifung on vorvorletzter and penultimate turn, up to five very small teeth, very small parietal tooth or missing, very small columellarer tooth, lower palatal tooth or missing, it can approach an upper palatal tooth and angularis be present.
The above compilation is very uncertain, since there is still no revision of the genus Vertigo. Some of the " subspecies " may also be separate species. The run also as a subspecies taxon Vertigo modesta Extima ( Westerlund, 1877) from Siberia is back now rather regarded as an independent species.
Endangering
In Germany the species is threatened with extinction ( hazard category 1). In Switzerland, it is classified as threatened with extinction. In Scotland and Austria it is at risk.