Ear-shaped glass snail

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Ear-shaped glass snail
Ear-shaped glass snail (Eucobresia diaphana)

Ear- shaped glass snail ( Eucobresia diaphana )

Systematics
Subordination : Land snails (Stylommatophora)
Superfamily : Limacoidea
Family : Glass snails (Vitrinidae)
Subfamily : Vitrininae
Genre : Eucobresia
Type : Ear-shaped glass snail
Scientific name
Eucobresia diaphana
( Draparnaud , 1805)

The ear-shaped glass snail ( Eucobresia diaphana ) 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 housing is still relatively large (in relation to the animal), but the animal can no longer retreat completely into the housing. It has up to 2.5 turns and reaches a diameter of 6 to 7 mm and a height of 3 to 4 mm. It is severely flattened to almost flat with a very large, inflated mouth. This takes up about half of the final diameter. The seam is hardly deepened. The transversely shaped mouth is very oblique to the axis of the winding. When viewed from above (on the apex), the edge of the mouth at the top is curved forward in the shape of a saddle. The navel is open.

The shell is thin and fragile. It is yellowish to whitish and translucent. The Protoconch shows very small pits that are regularly arranged in a spiral. The surface of the Teleoconch is smooth and shiny, apart from very fine, regular growth strips.

The body of the ear-shaped glass snail is usually deep black; however, animals with a light gray coat also occur in the higher altitudes. When stretched out, they reach a length of about 2 cm. The skin seam on the lower housing mouth is relatively wide and takes up about 35 to 50% of the turn. The apex of the housing is usually covered by a broad, tongue-shaped jacket flap. The radula is oxygnath. the marginal teeth are single-pointed. There are a total of 66 to 78 teeth per transverse row. There can be over 100 transverse rows in total.

Like all land snails, the animals are hermaphrodites. The penis is relatively large and club-shaped. The outer penis wall is glandular (penile gland). The proximal two thirds are surrounded by another tissue cover (penis cover). The spermatic duct is relatively long. It dips under the penis sheath and penetrates subapically into the penis. The penile retractor muscle attaches apically. is relatively long with a retractor in this species, the genital opening is relatively short. Two pillar structures are formed internally in the penis. In the female tract, the free fallopian tube is long and the vagina is short. The basal part of the stem of the spermathec is swollen almost spherically. The stem is short to moderately long stem. The bladder is small and ovoid. The vagina and penis open into a very short atrium.

Similar species

In the alpine glass snail ( Eucobresia nivalis ) the last turn is slightly less than half the diameter. In the case of the glacial glass snail ( Eucobresia glacialis ), the thread is no longer visible in the side view.

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

Geographical distribution and habitat

The main distribution area extends from the French Alps in the west through Switzerland, Austria, northern Italy to the northwestern Balkans (Slovenia, Croatia). In the north the distribution area extends to northern France, Belgium, the Netherlands and northern Germany, in the east to western and southern Poland, the Czech Republic and Slovakia. There are isolated occurrences in Bulgaria and Romania.

The animals live in cool and permanently moist places in the herbaceous vegetation of forests, floodplains, between stones, from the plains to the mountains (in Switzerland up to 2,900 m, in Bulgaria up to 2,600 m). At higher altitudes, they can also be found in more open biotopes, with bushes and grass.

Way of life

The species presumably has an annual generation change. At least at higher altitudes, eggs are laid in late summer. The rounded eggs are whitish with a shiny surface. The young hatch after about two weeks. The young animals feed on green and decaying plant parts, including detritus. Older animals also seem to accept animal food. The animals are occasionally active on mild winter days.

Taxonomy

The taxon was scientifically described for the first time in 1805 by Jacques Philippe Raymond Draparnaud as Vitrina diaphana . It is generally accepted and is consistently placed in the genus Eucobresia Baker, 1929.

The ear-shaped glass snail ( Eucobresia diaphana ) has several synonyms : Vitrina heynemanni Koch 1871, Vitrina jetschini Westerlund 1886, Helix limacina Alten 1812, Vitrina membranacea Koch 1876, Vitrina villae Pollonera 1884 and Helicolimax vitrea A. Férucobres 1821. Some authors also distinguish a subspecies Eucobres 1821 diaphana heynemanni Koch, 1871, which, however, has not found general recognition.

Danger

In Poland, populations are shrinking, the reasons are unknown. The species is therefore classified as endangered. It is also endangered in Rhineland-Palatinate. In Mecklenburg-Western Pomerania it is on the red list of endangered species in the category species with geographical restriction. According to the IUCN, however , the populations are not endangered in terms of their overall range. The species is not endangered in Germany either.

literature

  • Klaus Bogon: Land snails biology, ecology, biotope protection. 404 p., Natur Verlag, Augsburg 1990, ISBN 3-89440-002-1 , p. 182/83.
  • 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. 154.
  • Václav Pfleger: Mollusks. 192 p., Artia-Verlag, Prague 1984, p. 84.

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. ^ A b C. JPJ Margry: Changes in radula and jaw during life stages of Eucobresia diaphana (Draparnaud, 1805) (Gastropoda, Pulmonata, Vitrinidae). Basteria, 77 (1-3): 3-12, 2013 PDF
  3. ↑ Folco Giusti, Viviana Fiorentino, Andrea Benocci, Giuseppe Manganelli: A Survey of Vitrinid Land Snails (Gastropoda: Pulmonata: Limacoidea). Malacologia, 53 (2): 279-363, 2011 doi : 10.4002 / 040.053.0206 Academia.edu
  4. ^ Alexandru V. Grossu: Gastropoda Romaniae 4 Ordo Stylommatophora Suprafam: Arionacea, Zonitacea, Ariophantacea şi Helicacea. 564 S., Bucharest 1983, pp. 70-72.
  5. ↑ 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 , pp. 1485/86.
  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., Göttingen, Planet Poster Ed., 2012 ISBN 3-933922-75-5 , ISBN 978-3-933922-75-5 (S. 424)
  7. ↑ Zofia Ksiazkiewicz-Parulska, Bartłomiej Gołdyn: New records of Eucobresia diaphana (Draparnaud, 1805) in Western Poland. Folia Malacologica, 23: 235-237, 2015 doi : 10.12657 / folmal.023.018
  8. ↑ a b Beata M. Pokryszko, Tomasz K. Maltz: Rare and endangered terrestrial gastropods of Lower Silesia (SW. Poland) - current status and perspectives. Acta Universitatis Latviensis, 723 (Biology): 7-20, Riga 2007 ResearchGate
  9. ^ Jacques Philippe Raymond Draparnaud: Histoire naturelle des mollusques terrestres et fluviatiles de la France. Ouvrage posthumous. Pp. I-VIII (= 1-8), 1-134, Plassan, Renaud, Paris, Montpellier, 1805 [online at Biodiversity Heritahe Library], pp.
  10. ↑ AnimalBase: Eucobresia diaphana (Draparnaud, 1805)
  11. ↑ Fauna Europaea: Eucobresia diaphana (Draparnaud, 1805)
  12. ↑ MolluscaBase: Eucobresia diaphana (Draparnaud, 1805)
  13. ↑ a b Vollrath Wiese: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim 2014, ISBN 978-3-494-01551-4 (p. 234)
  14. ↑ Uwe Jueg, Holger Menzel-Harloff, Renate Seemann, Michael Zettler: Red list of endangered snails and mussels of the inland Mecklenburg-Western Pomerania. Ministry of the Environment of the State of Mecklenburg-Western Pomerania. Schwerin, 2002 PDF , p. 10.
  15. ↑ The IUCN Red List of Threatened Species: Eucobresia diaphana