Glacier glass snail
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Glacier glass snail ( Eucobresia glacialis ) |
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| Eucobresia glacialis | ||||||||||||
| ( Forbes , 1837) |
The glacial glass snail ( Eucobresia glacialis ) is a "half- nudibranch " from the family of glass snails (Vitrinidae), which is counted among the land snails (Stylommatophora). The animals can no longer withdraw into the small housing.
features
The right-hand winding case is ear-shaped with an almost flat thread. It is practically invisible in the side view. It has 2.5 slowly growing coils and measures 4.5 to 6.3 mm in diameter and 2.5 mm in height. The seam is hardly deepened. The mouth width is 4.5 mm, the mouth height 3.5 mm. The last turn is only a little wider than the thread. A navel is not developed. The mouth rim is straight and tapered thin. The transversely shaped mouth is very oblique to the axis of the winding. At the bottom of the mouth there is a wide skin seam that takes up about a third to a quarter of the width of the last turn. The outer edge of the mouth is rounded.
The shell is thin and fragile. It is yellowish horn-colored and translucent. The surface is slightly wrinkled radially and very shiny.
The coat is comparatively large and extends to the base of the eye wearer. In front it is dark gray with a dense dark mottling, the tentacles and the tail are dark gray. An almost black jacket rag covers the entire thread of the housing. The mantle extension over the breathing opening is finger-shaped.
In the hermaphroditic genitalia, the hermaphroditic duct (ductus hermaphroditicus) opens into the lower half of the short, approximately triangular protein gland (albumin gland). The egg ladder (spermoviduct) is elongated. The vas deferens leaving the prostate is quite short and penetrates the penis laterally, clearly subapical. The penis is very short and very thickened. The apical end is pointed. The penile retractor muscle is slightly subapical, but significantly closer to the apex than the point at which the spermatic duct enters the penis. There is an erectile tissue inside the penis.
The free fallopian tube (oviduct) is relatively short and thin, but the vagina, which is also short, is thickly swollen. A movable vaginal papilla is formed in the vagina between the free fallopian tube and the vagina. In adult animals, the basal part of the vagina is fused with the penis or jointly open into a long atrium; in juvenile animals, the vagina and penis are still separate. The sperm library has a short, comparatively thick stem. The bladder is large and ovoid. It comes to rest in the lower part of the egg ladder. The penis and vagina open into a long atrium.
Similar species
The glacial glass snail can only be distinguished from the summit glass snail ( Eucobresia pegorarii ) with certain anatomical certainty. The shell of the glacial glass snail has a slightly wider skin seam at the lower edge of the mouth. The outer edge of the mouth of the glacier snail is rounded, and that of the summit glass snail is slightly curved. The differences are blurred in individual cases. The glacial glass snail differs through its clearly thick, conical penis and its strongly thickened vagina.
The shell is also similar to that of the ear-shaped glass snail ( Eucobresia diaphana ). When viewed from above, the upper edge of the mouth of the glacier glass snail is slightly concave towards the beginning of the previous turn, while the ear-shaped glass snail is convex.
Geographical distribution and habitat
The species occurs only in the high alpine regions of the Alps of France, Switzerland, Austria and southern Germany (Allgäu and Berchtesgaden Alps). According to Alba et al. (2004) it is said to also occur in the Catalan Pyrenees.
It lives in moderately humid locations between rocks and herbaceous stands, on alpine meadows, lawns in the rock and scree slopes with vegetation almost exclusively above the tree line. In Switzerland it was found in the canton of Valais up to 2900 m above sea level. In Austria it occurs between about 1000 and 3100 m above sea level. In Switzerland it was found in the altitude belt between 2000 and 3000 m.
Way of life
reproduction probably takes place in late summer. The species certainly has a life cycle of several years. In August Lothar Forcart found juvenile animals, but also adults whose spermathec contained semen, i.e. This means that copulation need not have taken place long before. From the shape of the genital organs, Forcart concluded that the penis is not inserted during copulation, but that the movable vaginal papilla absorbs the sperm outside the body.
Taxonomy
The taxon was set up in 1837 by Edward Forbes as Vitrina glacialis . In the past, the taxon was also placed in the genera Phenacolimax Stabile, 1859 and Insulivitrina Hesse, 1923. The current position in the genus Eucobresia has not been questioned for some time.
Danger
The species is in the Red Lists of Germany and the Red List of Bavaria in the "Extremely rare" category. The IUCN has been made due to lack of data ( "Data Deficient") no assessment of stock situation.
Individual evidence
- ↑ 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.
- ↑ a b c d Lothar Forcart: Monograph of the Swiss Vitrinidae (Moll. Pulm.). Revue Suisse de Zoologie, 51: 629-678, 1944 Online at Biodiversity Heritage Library , pp. 654-657 as Insulivitrina glacialis .
- ↑ 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)
- ↑ David M. Alba, Antoni Tarruella Ruestes, Jordi Corbella Alonso, Manuel Vilella Tejedo, Glòria Guillén Mestre, Lluís Prats Pi, Josep Quintana Cardona: Addenda a la llista dels mol·luscos. Spira, 1 (4): 1-10, 2004 PDF continentals de Catalunya
- ^ Edward Forbes: On the comparative elevation of Testacea in the Alps. Magazine of Zoology and Botany 1 (3): 257-259. Edinburgh, 1837 Online at the Biodiversity Heritage Library .
- ↑ 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. 156 as Phenacolimax glacialis .
- ↑ AnimalBase: Eucobresia glacialis (Forbes, 1837)
- ↑ Fauna Europaea: Eucobresia nivalis (Dumont & Mortillet, 1854)
- ↑ MolluscaBase: Eucobresia glacialis (Forbes, 1837)
- ^ Vollrath Wiese: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim 2014 ISBN 978-3-494-01551-4 (p. 237)
- ↑ Bavaria's Red List of Endangered Mussels and Snails PDF
- ↑ The IUCN Red List of Threatened Species: Eucobresia glacialis