Beaded grain snail

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Beaded grain snail
Beaded grain snail (Granaria frumentum)

Beaded grain snail ( Granaria frumentum )

Systematics
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Superfamily : Pupilloidea
Family : Corn snails (Chondrinidae)
Genre : Granaria
Type : Beaded grain snail
Scientific name
Granaria frumentum
( Draparnaud , 1801)

The beaded grain snail ( Granaria frumentum ) is a terrestrial species of snail from the family of grain snails (Chondrinidae).

features

The case is 6.5 to 8 mm high and measures 2.7 to 3 mm in thickness (width). The height-width index fluctuates, so that smaller (lower) specimens are more stocky with relatively greater thickness. The housing is highly conical, and in the upper third it tapers rapidly towards the apex, i. the first five to six, flat, rounded turns increase in width much more quickly than the last turns. A total of nine to ten turns are formed, which are separated from one another by a relatively flat seam. The skin is translucent and brownish to gray in color. The surface is largely smooth and shows only fine, dense and regular growth strips. On the last passage a strong, white neck bulge forms, which narrows the umbilical area. The mouth edge is turned over and greatly enlarged. It is interrupted in the area of ​​the parietal region. The mouth is narrowed by the bulge in the neck and a fold of the palate or eight teeth (or folds) protrude into it. The four palatal teeth are always well developed and fuse, giving way to the other four teeth with the palatal callosity. The teeth shine through the housing and form lines that extend over about half a turn, i.e. until the beginning of the formation of teeth in the mouth. The angular tooth is connected to the edge of the mouth, the parietal tooth and the two columellar teeth are close together.

Large case 1.2 cm long

Geographical occurrence and habitat

The beaded grain snail is widespread in Central Europe, but very dispersed. It occurs only in areas with limestone or dolomite subsoil. The occurrence ranges from eastern and south-eastern France, through Switzerland, southern and central Germany (to southern Lower Saxony (Harz)), Austria, the Czech Republic, Slovakia, Hungary (Bükk Mountains) and the Balkan Peninsula to Bulgaria , also isolated in small deposits (Deportation?) In northern France, Belgium , northern Germany and south-eastern Poland.

The species prefers xerothermal, short-grass slopes at the foot of rocks, walls, scree slopes, also meadows in limestone-rich locations, more rarely on other rocks.

Way of life

In or after rain, the animals crawl on stones and rocks, but also on roots, at the foot of bushes, or on grass stalks. When it is dry, they hide under stones, between rubble or in crevices. They overwinter on rocky sites under dead plant parts.

In grassy biotopes, the bulbous grain snail occasionally acts as an intermediate host of the lesser liver fluke , especially when other intermediate hosts (e.g. Helicella itala or Xerolenta obvia ) are missing. Because of its rarity and habitat, it does not play a major role as a vector for dicrocoeliosis .

Systematics

The bulging grain snail is the type of the genus Granaria Held, 1838. It was first scientifically described in 1801 by Jacques Philippe Raymond Draparnaud as the pupa frumentum . The species name is valued as a noun in aposition; the ending is therefore not adapted to the gender of the genus. Five subspecies are eliminated:

  • Granaria frumentum appenina (Küster, 1850)
  • Granaria frumentum atracta (Pilsbry 1918)
  • Granaria frumentum frumentum (Draparnaud 1801), the nominate subspecies
  • Granaria frumentum hungarica (Kimakowicz 1890)
  • Granaria frumentum subaii Fehér, Deli & Sólymos, 2010

swell

Individual evidence

  1. ↑ Species summary for Granaria frumentum at Animalbase

literature

  • Klaus Bogon: Land snails biology, ecology, biotope protection. 404 p., Natur Verlag, Augsburg 1990, ISBN 3-89440-002-1 .
  • Rosina Fechter and Gerhard Falkner: molluscs. 287 p., Mosaik-Verlag, Munich 1990, (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 .
  • Ewald Frömming: Biology of the Central European Landgastropods. 404 p., Duncker & Humblot, Berlin 1954.
  • 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 .
  • Zoltán Fehér, Tamás Deli and Peter Sólymos: Revision of Granaria frumentum (Draparnaud 1801) (Mollusca, Gastropoda, Chondrinidae) subspecies occurring in the eastern part of the species' range. Journal of Conchology, 40 (2): 201-218, 2010.

On-line

Web links

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