Short glass snail

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Short glass snail
Short glass snail (Vitrinobrachium breve)

Short glass snail ( Vitrinobrachium breve )

Systematics
Subordination : Land snails (Stylommatophora)
Superfamily : Limacoidea
Family : Glass snails (Vitrinidae)
Subfamily : Vitrininae
Genre : Vitrinobrachium
Type : Short glass snail
Scientific name
Vitrinobrachium breve
( A. Férussac , 1821)

The short glass snail ( Vitrinobrachium breve ) is a half-nudibranch from the family of glass snails (Vitrinidae), which belongs to the land snails (Stylommatophora). The animals can no longer pull the soft body back into the small housing.

features

The right-hand wound case is very flat ear-shaped. It has a width of 5 to 5.5 mm. It has 1 3/4 to 2 turns slightly arched at the top, which are separated from each other by a flat seam. The end turn has in the apical view at the mouth about two thirds of the total diameter. The skin seam on the underside and the spindle side is very distinct. It extends inward to the base of the spindle. There is no navel. The mouth is large, egg-shaped and is very crooked to the axis of the coil. The upper edge is slightly concave after the approach to the previous turn. The mouth rim is straight and fragile.

The shell is thin and fragile. It is slightly greenish in color and very translucent. The surface of the housing is very finely wavy striped and shiny. The embryonic housing is milky and smooth with numerous small greens, which are arranged in spiral rows.

The soft body is dark gray or black and measures 10 to 14 mm in length and can no longer retract into the housing. The coat is very large and extends in front of the edge of the case to the base of the eye wearer. The jacket lobe reaches the housing appendix and covers it; it is comparatively large. The breathing opening is a straight slit.

In the hermaphroditic genitalia, the hermaphroditic gland is small and very compact. The hermaphroditic duct is almost straight or only very slightly twisted. It penetrates the blind sack-like end of the elongated egg ladder (spermoviduct). The protein gland (albumin gland) has a grape-like shape. The free fallopian tube is very short. The sperm library has a short stem. The small, elongated bladder lies against the egg ladder. The passage of the spermatheque leads directly into the long atrium. A vagina is not formed.

In the male tract, the vas deferens is moderately long and joins the penis subapically. The penis is sack-shaped and curved and moderately long. In the lower part it is surrounded by a tissue cover. Inside, it has a structure similar to Glans . The penis reactor muscle attaches apically. In the sarcobelum (or stimulator), which opens into the atrium and opposite the penis, there is a so-called copulation arm. In the rest position, it is tubular and ends in the rear part in a spherical bladder that is surrounded by glandular tissue. This posterior part opens into the anterior part with a spherical papilla. A suction cup sits on this papilla.

Similar species

In the Trentino glass snail ( Vitrinobrachium tridentinum ) the apex of the shell is flatter, the first turns are more tightly rolled up, and the end turn is wider at the mouth. There are a little more turns. Vitrinobrachium baccettii only differs in the genital apparatus.

Distribution of the species (according to Welter-Schultes, 2012)

Geographical distribution and habitat

The distribution area extends from the northern Alps to southern Germany and the Czech Republic. In the Rhine Valley on to the Netherlands. There are also isolated occurrences west of Ansbach in Franconia and in southern Bavaria (Isar Valley). Occurrences near Görlitz (Saxony) and in Mecklenburg-Western Pomerania are explained with anthropogenic spread. The occurrences in the southern Alps are separated by the main Alpine ridge. This occurrence extends into Tuscany. The species occurs from the plains to the montane region, most frequently between 300 and 700 m. But they are rather rare above 1000 m above sea level. In southern Switzerland it rises to 1,500 m above sea level.

The animals live in moist, light deciduous forests, especially alluvial forests with mosses, or deep soils under stones or on rocky ground. In the meantime, they have also been anthropogenically displaced into cultivated land such as gardens and parks.

Way of life

The animals become sexually mature at three to four months. Depending on the population, they have one or two breeding seasons. The populations with a reproductive period mate in October and then lay up to 100 eggs in clutches of 6 to 30 eggs. The egg is ovate, 1 to 1.5 mm long, 0.5 to 1 mm in thickness. The eggs are hidden under damp mosses. The animals die after laying eggs. If populations have two reproductive phases, the first egg-laying takes place between the beginning of April and the end of June, the second egg-laying between the end of December and the end of February. Accordingly, the animals are between 10 and 17 months old, but under laboratory conditions. The young animals hatch after 3 to 8 weeks, depending on the temperature. The coat of the young is initially whitish, after about a week it becomes bluish and after another week it becomes blue-black.

During mating, the tubular copulation arm is turned inside out and stretched out of the genital opening. The papilla from the rear part with the suction cup now comes to lie at the very front and forms the tip of the outstretched and very mobile copulation arm. The partners hold on to each other with the suction cup of the copulation arm. The penis, which is also everted, encompasses the copulation arm of the other partner. The parcel of sperm enveloped by the secretion of the penis glands is attached to the copulation arm of the other partner. The sperm packets are transported into the genital opening (atrium) when the genital organs are withdrawn.

Taxonomy

The taxon was set up in 1821 by André Étienne d'Audebert de Férussac in the original combination Helicolimax brevis . It is the type species of the genus Vitrinobrachium Künkel, 1929. The taxon is generally recognized.

Danger

According to Vollrath Wiese, the species is not endangered in Germany. However, it is considered endangered in Rhineland-Palatinate, as well as in Switzerland.

literature

  • Rosina Fechter and Gerhard Falkner: molluscs. 287 pp., Munich, Mosaik-Verlag 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, pp. 149/50.

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. ↑ Anatolij A. Schileyko: Treatise on Recent Terrestrial Pulmonate Molluscs Part 11 Trigonochlamydidae, Papillodermidae, Vitrinidae, Limacidae, Bielziidae, Agriolimacidae, Boettgerillidae, Camaenidae. Ruthenica, Supplement 2 (11): 1467-1626, Moscow 2003 ISSN  0136-0027 , p. 1486.
  3. ↑ Lothar Forcart: Monograph of the Swiss Vitrinidae (Moll. Pulm.). Revue Suisee des Zoologie, 51: 629-678, 1944 Online at Biodiversity Heritage Library , pp. 639-641.
  4. ^ A b Karl Künkel : Comparative experimental study on Vitrina elongata Draparnaud and Vitrina brevis Férussac. Zoological Yearbooks, Department of General Zoology and Animal Physiology 52: 399-432, Jena 1933.
  5. ↑ Folco Giusti, Viviana Fiorentino, Andrea Benocci, Giuseppe Manganelli: A Survey of Vitrinid Land Snails (Gastropoda: Pulmonata: Limacoidea). Malacologia, 53 (2): 279-363, 2011 Academia.edu , p. 348.
  6. ↑ 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., Planet Poster Ed., Göttingen 2012, ISBN 3-933922-75-5 , ISBN 978-3-933922-75-5 (p. 430)
  7. ^ Ewald Frömming: Biology of the Central European Landgastropods. 404 S., Duncker & Humblot, Berlin, 1954, pp. 115-117.
  8. ^ Karl Künkel: Experimental study on Vitrina brevis Férussac. Zoological yearbooks, Department of General Zoology and Animal Physiology, 46: 575-626, Jena 1929.
  9. ↑ AnimalBase: Vitrinobrachium breve (Férussac, 1821)
  10. ↑ Fauna Europaea: Vitrinobrachium breve (A. Ferussac, 1821)
  11. ↑ MolluscaBase: Vitrinobrachium breve (A. Férussac, 1821)
  12. ↑ a b Vollrath Wiese: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim 2014, ISBN 978-3-494-01551-4 (p. 231).