Alemannic grass snail

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Alemannic grass snail
Systematics
Subordination : Land snails (Stylommatophora)
Superfamily : Pupilloidea
Family : Grass snails (Valloniidae)
Subfamily : Valloniinae
Genre : Vallonia
Type : Alemannic grass snail
Scientific name
Vallonia alamannica
Geyer , 1908

The Alemannic grass snail ( Vallonia alamannica ), also Alemannic grass snail, is a species of snail from the family of grass snails (Valloniidae) that lives on land ; the family belongs to the subordination of land snails (Stylommatophora). It is a controversial taxon that some authors rate as a synonym for the Swabian grass snail . More recent studies treat the taxon as an independent species again.

features

The disc-shaped shell of the Alemannic grass snail has a height of 1.4 to 1.8 mm and a width of 2.5 to 2.9 mm. It has 3 1/8 to 3 3/4 turns, rounded on the periphery, which increase regularly. The hem of the mouth is turned up like a brim, there is a strong lip on the inside. The upper starting point of the turn rises in the last quarter of the turn from a position well above the periphery of the penultimate passage evenly to the lower third of the previous passage. The mouth is extremely sloping, the actual mouth rim is thin. The very wide open umbilicus is eccentric; H. is not exactly in the middle of the case, but slightly shifted to the edge. The case is brownish and the surface is striped, which gives the case a silky sheen. The embryonic housing shows a weak spiral stripe.

Similar species

The Alemannic grass snail differs from the Swabian grass snail ( Vallonia suevica ) primarily in its size . The last passage sinks continuously at Vallonia alamannica , while at Vallona suevica just before the mouth it initially runs horizontally or even rises slightly and then drops more or less steeply. Vallonia alamannica has at least half a deal more. The mouth is less widened and the inner lip is less developed.

Geographical distribution and habitat

The range of the species is limited to Baden-Württemberg (upper Neckar and upper Danube). The occurrence in Lower Austria, which can be found in some plants, has proven to be incorrectly identified (Gerber). The species lives on natural meadows in river valleys, but is very rare there.

Taxonomy

The taxon was introduced into scientific literature in 1908 by David Geyer as Vallonia tenuilabris var. Saxoniana Sterki ( alamannica n.var.?). Ehrmann already listed the taxon as an independent species in Die Tierwelt Mitteleuropas . Other authors (e.g. Zilch) assessed the taxon as a subspecies of Vallonia tenuilabris . Michael Kerney (et al.), However, lead the taxon again as an independent species. In 1996, Jochen Gerber declared the taxon to be a form of the Swabian grass snail ( Vallonia suevica ). Most authors followed suit. But as early as 1997 Günter Schmid , and then Wolfgang Rähle (1939–2019) in 2011, questioned Jochen Gerber's conclusions. Therefore Vollrath Wiese now again lists the taxon as an independent species, but emphasizes that the taxonomic status is still unclear.

Danger

Since the taxon was treated (again) as a synonym of Vallonia suevica until recently , it is not included in the Red List. Vollrath Wiese suggests classification as "extremely rare". The International Union for Conservation of Nature and Natural Resources (IUCN) classifies the species as "Data deficient".

The taxon was on the “Red List” before it was synonymous (1996) and was classified as critically endangered (status 1982).

supporting documents

literature

  • Michael P. Kerney, Robert AD Cameron & Jürgen H. Jungbluth: The land snails of Northern and Central Europe. 384 p., Paul Parey, Hamburg & Berlin 1983, ISBN 3-490-17918-8 (p. 126/7)
  • Wolfgang Rähle: Remarkable Vallonia finds in the “Wertwiesen” nature reserve near Horb am Neckar (Freudenstadt district, Baden-Württemberg). Announcements of the German Malacozoological Society, 86: 1–5, Frankfurt / M. PDF
  • Vollrath Wiese: Germany's land snails. 352 S., Quelle & Meyer, Wiebelsheim 2014 ISBN 978-3-494-01551-4 (p. 95/6) (in the following abbreviated, meadow, land snails with corresponding page number)

Individual evidence

  1. ^ Dietrich Geyer: Contributions to the mollusc fauna of Swabia II. Vallonia. Annual books of the Association for Patriotic Natural History in Württemberg, 64: 305-330, Stuttgart 1908. Online at www.biodiversitylibrary.org (pp. 324–325)
  2. ↑ Paul Ehrmann: Mollusken (molluscs). In: Paul Ehrmann, Paul Brohmer, G. Ulmer (Hrsg.): Die Tierwelt Mitteleuropas: a manual for their determination as a basis for faunistic-zoogeographical work; 2. Mollusca, Crustacea, Isopoda, Myriapoda, Lfg. 1,264 p., Leipzig, Quelle & Meyer 1937
  3. ^ Adolf Zilch: The types and typoids of the Senckenberg Nature Museum . 43: Mollusca, Pupillacea 2 (Valloniidae, Pleurodiscidae). Archive for molluscology.
  4. ↑ AnimalBase: Species summary for Vallonia suevica Geyer, 1908
  5. ↑ Fauna Europaea
  6. ↑ Günter Schmid: "Malacological twitches". Snapshots of the Malakofauna in Baden-Württemberg. Publications for nature conservation and landscape management in Baden-Württemberg, 71/72: 719-858, Karlsruhe 1997.
  7. ↑ a b Wiese, Landschnecken, pp. 95/6.
  8. ↑ Vallonia allamanica in the endangered Red List species the IUCN 1996. Posted by: Mollusc Specialist Group, 1996. Accessed July 15, 2014. (wrong here allamannica written!)
  9. ^ Red Lists Baden-Württemberg (until 2005) snails and mussels. Processing status: September 1982 by Jürgen H. Jungbluth and Reiner Bürk (with additions by Günter Schmid) / 12 / ( Memento from July 25, 2014 in the Internet Archive )

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