Small forest snail

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Small forest snail
Small forest snail (Cochlostoma septemspirale)

Small forest snail ( Cochlostoma septemspirale )

Systematics
Superordinate : Caenogastropoda
Order : Architaenioglossa
Superfamily : Cyclophoroidea
Family : Forest snails (Cochlostomatidae)
Genre : Cochlostoma
Type : Small forest snail
Scientific name
Cochlostoma septemspirale
( Razoumowsky , 1789)

The small forest snail ( Cochlostoma septemspirale ) is a terrestrial snail species from the family of forest snails (Cochlostomatidae), which belongs to the order Architaenioglossa .

features

The right-hand winding, conical-tower-shaped case is 7 to 8 mm high and 3.8 mm wide (6.7 to 10.2 × 3.2 to 4.4 mm). It has about 8½ turns (7 to 10 turns), which are well rounded and separated from each other by a clear seam. The sideline (from the maximum bulge of the last gallery to the furthest bulges of the older gallery to the apex) is almost straight. The last turn is greatly expanded. The whitish mouth is almost round, the edge of the mouth is thickened and slightly curved outwards. This outer area is divided into an inner and an outer part. The inside of the mouth is thickened by a thick, white lip. The navel is very narrow and needle-shaped; it is partially covered by the bent edge of the mouth. The housing is gray or white-gray to slightly reddish-brown in color with three rows of spirally running, more or less distinct dark spots. The surface is strongly ribbed, about six to eight ribs per millimeter. The operculum sitting on the top of the foot end is thin and not calcified. The animal can withdraw deep into the housing and close the opening with the operculum. The front part of the head is elongated like a snout. The feelers are comparatively thick and conical in shape. At its base, the eyes sit on small mounds. The soft body is gray to dark gray in color.

The soft body is dark gray to black in color. The animals are of separate sexes, a slight sexual dimorphism is recognizable. The housings of the females are a little slimmer, but a little larger. The mouth is somewhat reduced in height in the females. The volume of the housing of the females is approximately 1/5 larger than that of the housing of the males. The last contact with the housings of the females is slightly less pigmented than with the males, and the mean density of the ribs is higher in the females. All characteristics overlap strongly and taken alone, no characteristic is suitable for reliably differentiating between females and males on the basis of the housing. In a multivariate analysis of the five characteristics described above, however, it was possible to reliably assign 90% of all housings to a gender.

Geographical distribution and habitat

The original distribution area mainly comprised southern Europe from the Pyrenees, south and south-east France in the west to the Balkan peninsula in the east. North of the Alps there are only a few occurrences in the Upper Rhine Valley, in the Wutach region of the Black Forest, in the Odenwald, in the southeastern Bavarian Limestone Alps and the Danube Valley near Regensburg. In the meantime the species has also been anthropogenically displaced or settled in Belgium and England .

The species lives on / under exposed rocks, between and on stones of scree slopes in illuminated biotopes, but also in dark biotopes in the leaf litter of shady forests on calcareous soil, in dry as well as moist locations. In Switzerland they rise to heights of over 2000 m.

Way of life

The small forest snail feeds on algae and lichens that grow on wood and stones as well as on parts of rotting plants. After rain they are often found in large numbers on exposed rocks, but also on pieces of wood and the bark of trees. Here they graze the surface vegetation. When it is dry, they usually retreat under the rocks or pieces of dead wood.

The animals are not very active and very slow. They are only active in damp weather. In dry weather or on the ground, the housing is closed with the operculum. In winter, the activity stops at temperatures below 6 to 7 ° C and the animals hibernate. To do this, they withdraw under stones, leaf litter or grass mats.

The eggs are laid from April to October, but mainly in May and June. The eggs have a diameter of 1.0 to 1.1 mm, rarely smaller. They are wrapped in a layer of mucus and feces by the female and buried about an inch deep in the ground. The clutches contain up to ten eggs. The young hatch from the egg shell after 45 to 60 days. Adult size is reached after about a year.

Taxonomy

The taxon was first scientifically described in 1789 by Count Grigorij de Razoumowsky as Helix Septem-Spiralis . In 1830 Georg Jan introduced Cochlostoma as a subgenus of Cyclostoma "Draparnaud". However, the latter taxon does not come from Jacques Philippe Raymond Draparnaud , but from Jean-Baptiste de Lamarck , who first described the genus Cyclostoma in 1799. Jan (1830: p. 6) gave no description of his new subgenus Cochlostoma , but listed six species that should belong to the new subgenus. The genre was thus validly established according to the standards of the time. Wenz (1923: p. 1773) identified Cyclostoma maculatum Draparnaud, 1805, a more recent synonym of Helix Septem-Spiralis Razumowsky, 1789 as the type species. This means that Helix Septem-Spiralis Razumowsky, 1789 is not formal, but is de facto a type of the genus Cochlostoma Jan , 1830 (and also of the subgenus Cochlostoma (Cochlostoma) Jan, 1839).

The genus Cochlostoma is now divided into several sub-genres: Cochlostoma (Cochlostoma) in January, 1830, Cochlostoma (Obscurella) Clessin, 1889, Cochlostoma (Auritus) Westerlund, 1883, Cochlostoma (Holcopoma) Kobelt & Moellendorff, 1899 Cochlostoma (turritus) Westerlund, 1883. The family structure follows the Fauna Europaea.

Some authors distinguish between two subspecies of the lesser forest snail:

  • Cochlostoma (Cochlostoma) septemspirale septemspirale (Razoumowsky, 1789)
  • Cochlostoma (Cochlostoma) septemspirale heydenianum (Clessin, 1879). The subspecies is also known as the thick-lipped forest snail.

However, there are many transitional forms, which is to be expected in the contact area, but not to the extent described by Edlinger & Mildner (1979), on the other hand, both subspecies occur together in many locations. According to this, a subdivision into subspecies cannot be maintained and is not (no longer) found in the fauna of Europaea.

Danger

The small forest snail is classified as extremely rare in Germany's 2012 Red List.

supporting documents

literature

  • Klaus Bogon: Land snails biology, ecology, biotope protection. Natur Verlag, Augsburg 1990, ISBN 3-89440-002-1 , p. 100.
  • Rosina Fechter, Gerhard Falkner: molluscs (= Steinbach's natural guide 10). Mosaik-Verlag, Munich 1990, ISBN 3-570-03414-3 , p. 140.
  • Serge Gofas: The systematics of Pyrenean and Cantabrian Cochlostoma (Gastropoda, Cyclophoroidea) revisited. In: Journal of Natural History. 35 (9) 2001, doi : 10.1080 / 002229301750384301 , pp. 1277-1369.
  • Michael P. Kerney, RAD Cameron, Jürgen H. Jungbluth: The land snails of Northern and Central Europe. Paul Parey, Hamburg / Berlin 1983, ISBN 3-490-17918-8 , pp. 84-85.
  • Václav Pfleger: Mollusks. Artia-Verlag, Prague 1984, 192 pages.
  • Wilhelm Wenz: Gastropoda extramarina tertiaria. In: Carl Diener (Ed.): Fossilium catalogus. Volume 1: Animalia. Pars 17 + 23, Berlin 1923, pp. 1–1862.
  • Vollrath Wiese: Germany's land snails. Quelle & Meyer, Wiebelsheim 2014, ISBN 978-3-494-01551-4 , 352 pages.

Individual evidence

  1. ↑ a b Bogon, Landschnecken, pp. 72–74.
  2. ↑ a b Wiese, Landschnecken, p. 25.
  3. ↑ a b AnimalBase - Cochlostoma septemspirale.
  4. ↑ Fabian Reichenbach, Hannes Baur, Eike Neubert: Sexual dimorphism in shells of Cochlostoma septemspirale (Caenogastropoda, Cyclophoroidea, Diplommatinidae, Cochlostomatinae). In: Zookeys. 2012; (208), pp. 1-16. doi : 10.3897 / zookeys.208.2869
  5. ^ Count Grigorij de Razoumowsky: Histoire naturelle du Jorat et de ses environs; et celle des trois lacs de Neufchatel, Morat et Bienne; précédées d'un essai sur le climat, les productions, le commerce, les animaux de la partie du Pays de Vaud ou de la Suisse Romande, qui entre dans le plan de cet ouvrage. Tome premier. I-XVI, Mourer, Lausanne 1789, p. 278 ( online at Biodiversity Heritage Library ).
  6. ^ Georg Jan: Scientiae naturalis cultoribus. Conspectus methodicus testaceorum in collectione mea exstantium anno 1830. Parma 1830, pp. 1-8 ( online at uni-goettingen.de).
  7. ↑ Jean-Baptiste de Lamarck: Prodrome d'une nouvelle classification des coquilles, comprenant une rédaction appropriée des caractères génériques, et l'établissement d'un grand nombre de genres nouveaux. Mémoires de la Société d'Histoire Naturelle de Paris. 1, pp. 63-91, 1 Tableau, Paris 1799, p. 74 ( online at Biodiversity Heritage Library ).
  8. ↑ Fauna Europaea - Cochlostoma Jan, 1830
  9. ↑ Gofas, 2001, p. 1283.
  10. ^ Paul Mildner and Ursula Rathmayr: Red list of the molluscs of Carinthia (Mollusca). In: WEH Holzinger, Paul Mildner, T. Rottenburg, C. Wieser (eds.): Red lists of endangered animals in Carinthia. Nature conservation in Carinthia, 15, Klagenfurt 1999, pp. 643-662 ( PDF ).
  11. ^ Karl Edlinger, Paul Mildner: Monograph of the Prosobranch genus Cochlostoma living in Carinthia. In: Carinthia II. 169./89. Year, Klagenfurt 1978, pp. 281–304 ( PDF on ZOBODAT ).
  12. ↑ Margret Binot-Hafke, Sandra Balzer, Nadine Becker, Horst Gruttke, Heiko Haupt, Natalie Hofbauer, Gerhard Ludwig, Günter Matzke-Hajek, Melanie Strauch (Red.): Red List of Endangered Animals, Plants and Mushrooms in Germany. Volume 3: Invertebrates (Part 1). 716 p., Federal Agency for Nature Conservation, Bonn-Bad Godesberg 2012 (Nature Conservation and Biological Diversity 70 (3)) ISBN 978-3-7843-5231-2 .

On-line

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