Alm glass snail

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Alm glass snail
Alpine glass snail (Eucobresia nivalis)

Alpine glass snail ( Eucobresia nivalis )

Systematics
Subordination : Land snails (Stylommatophora)
Superfamily : Limacoidea
Family : Glass snails (Vitrinidae)
Subfamily : Vitrininae
Genre : Eucobresia
Type : Alm glass snail
Scientific name
Eucobresia nivalis
( Dumont & Mortillet , 1854)

The alpine glass snail ( Eucobresia nivalis ) is a "half- nudibranch " from the family of glass snails (Vitrinidae), which is counted among the land snails (Stylommatophora). The animals can no longer completely withdraw into the small housing.

features

The right-hand winding case is ear-shaped with a low thread; however, the animal can no longer fully withdraw into the housing. It has up to 2.5 turns that slowly expand; the last turn is very bloated. The housing is more compact in shape and has a diameter of 4 to 6 mm and a height of 3 to 4.5 mm. The last turn takes up a little more than half the diameter of the case. The turns are slightly arched at the top, the seam is clear. The skin seam at the lower edge of the mouth takes up about a quarter of the last turn. The mouth is ovoid when viewed from above. The mouth surface is very oblique to the coiling matter of the coils. The mouth edge is straight and pointed. In the dorsal view, the upper edge of the mouth bends like a saddle. There is no navel.

The shell is very thin and fragile. The surface is very glossy. There are only very fine strips of growth.

The soft body is gray to dark gray marbled. The mantle flap is relatively small and does not cover the apex of the housing. Stretched out or crawling, the animal becomes up to 14 mm long. The hermaphroditic genitalia is very compact. The spermatic duct (vas deferens) is very short in the male genital tract. The penis is also very short and thick. It is almost completely enclosed by a tissue cover. The spermatic duct runs under this sheath and opens subapically into the penis. The penile retractor muscle attaches directly apically. In the female part, the free fallopian tube (oviduct) and vagina are very short. The sperm library has a very short but thick stem. The bladder is oblong-egg-shaped or oblong-elliptical and proportionally very large. It attaches itself to the lower egg ladder (spermoviduct). The vagina and penis open into a comparatively very long atrium.

Similar species

The shell is smaller than that of the ear-shaped glass snail ( Eucobresia diaphana ). The hem of the skin is narrower and the mantle flap is also smaller; it usually does not cover the apex of the housing. The mouth is a little higher. In the genital system, the penis is much shorter, as are fallopian tubes and vagina, but the atrium is longer.

Distribution in Europe (according to Welter-Schultes, 2012)

Geographical distribution and habitat

The species lives mainly in the higher regions of the Alps (eastern France, Switzerland, Austria and northern Italy) and the Carpathian Mountains (Slovakia, southern Poland, western Ukraine, Romania). In Germany it occurs in the Bavarian Alps and also in higher elevations of the Elbe Sandstone Mountains and the Thuringian Forest. In Poland and the Czech Republic it was found in the Sudetes. In the Alps it is mainly found between 2000 and 2500 m above sea level, in the canton of Valais even up to 3100 m above sea level.

The animals live in swampy areas on alpine pastures and mountain forests, most often on damp, stone-covered slopes, often even on the edge of snowfields above the tree line.

Way of life

The animals are very agile; they can move fairly quickly at 12-14mm / s. In Poland, the animals lay their eggs in autumn and die. The eggs overwinter and the young hatch in spring. The species is believed to have a two-year cycle. Possibly the animals live "as the weather allows".

Taxonomy

The taxon was established in 1854 by François Dumont and Gabriel Mortillet in their comprehensive work Histoire des mollusques terrestres et d'eau douce vivants et fossiles de la Savoie et du Bassin du Léman in the original combination Vitrina nivalis . It is generally recognized and is placed in the genus Eucobresia Baker, 1929.

Danger

According to the IUCN , insufficient data is available to assess the stock situation. However, the trend is a decrease in populations. In Bavaria the species is considered endangered. Throughout Germany it is listed under the heading "Extremely rare", as well as in the Red List of Saxony's Mollusks.

literature

  • Rosina Fechter, Gerhard Falkner: Mollusks. 287 p., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 , p. 172.
  • Michael P. Kerney, RAD Cameron, Jürgen H. Jungbluth: The land snails of Northern and Central Europe. 384 pp., Paul Parey, Hamburg & Berlin 1983, ISBN 3-490-17918-8 , p. 155.

Individual evidence

  1. ↑ Jürgen H. Jungbluth, Dietrich von Knorre: Trivial names of land and fresh water mollusks in Germany (Gastropoda et Bivalvia). Mollusca, 26 (1): 105-156, Dresden 2008 ISSN  1864-5127 , p. 124.
  2. ^ Alexandru V. Grossu: Gastropoda Romaniae 4 Ordo Stylommatophora Suprafam: Arionacea, Zonitacea, Ariophantacea şi Helicacea. 564 S., Bucharest 1983, pp. 72-73.
  3. ↑ a b c Francisco W. Welter-Schultes: European non-marine molluscs, a guide for species identification = identification book for European land and freshwater mollusks. A1-A3 S., 679 S., Q1-Q78 S., Göttingen, Planet Poster Ed., 2012 ISBN 3-933922-75-5 , ISBN 978-3-933922-75-5 (S. 424)
  4. ↑ Tomasz Umiński: Life cycles in some Vitrinidae (Mollusca, Gastropoda) from Poland. Annales Zoologici, 33 (2): 17-33, Warsaw, 1975 PDF
  5. ^ François Dumont, Gabriel Mortillet: Histoire des mollusques terrestres et d'eau douce vivants et fossiles de la Savoie et du Bassin du Léman. Bulletin de la Société d'Histoire Naturelle de Savoie, 1852: 14-142 [1852], 1-78 [1853], 81-152 [1854], 239-248 [1855]. Chambéry, 1852-1855
  6. ↑ AnimalBase: Eucobresia nivalis (Dumont & Mortillet, 1854)
  7. ↑ Fauna Europaea: Eucobresia nivalis (Dumont & Mortillet, 1854)
  8. ↑ MolluscaBase: Eucobresia nivalis (Dumont & Mortillet, 1854)
  9. ↑ a b Vollrath Wiese: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim 2014, ISBN 978-3-494-01551-4 (p. 235)
  10. ↑ The IUCN Red List of Threatened Species: Eucobresia nivalis
  11. ↑ Katrin Schniebs, Heike Reise, Ulrich Bößneck: Red List of Mollusks of Saxony. State Office for Environment and Geology, Free State of Saxony, 2006. PDF