White slice snail

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White slice snail
White pancake snail (Lucilla singleyana)

White pancake snail ( Lucilla singleyana )

Systematics
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Superfamily : Punctoidea
Family : European slugs (Helicodiscidae)
Genre : Lucilla
Type : White slice snail
Scientific name
Lucilla singleyana
( Pilsbry , 1889)

The white disk snail ( Lucilla singleyana ) is a species of snail in the family of the disk snail (Helicodiscidae) from the suborder of the land snail (Stylommatophora). The species was probably introduced anthropogenic from North America to Europe.

features

The right-hand wound, small case is almost disc-shaped; In the side view, the thread protrudes very little beyond the penultimate turn. It measures up to 3 mm in width and 1.2 mm in height (W / H index = 2.5). The 3½ to 4 turns expand slowly and regularly and are well arched on the periphery. The seam is comparatively deep. The navel is very broad and open; it takes up about a third of the case width. The mouth is round to slightly elliptical, but strongly indented by the previous turn. The mouth opening is at an angle to the winding axis. The edge of the mouth is simple, straight and not reinforced.

The casing is yellowish-brown, the periostracum is colorless. The shell is thin, fragile and translucent. The surface has fine strips of growth at irregular intervals. This makes the surface shiny. At high magnification, faint spiral stripes can be seen in some individuals.

Due to their way of life, the animals have reduced their eyes deep in the ground.

Similar species

The umbilicus of the white disc snail is somewhat flatter and wider than the umbilicus of the greenish disc snail ( Lucilla scintilla ), the shell is significantly larger in the adult stage (about 3 mm by 2.2 mm). In addition, the shell of the white disc snail is almost flat, disk-shaped, while the greenish disc snail is very flat and conical. In the side view, the thread of the white disc snail can hardly be seen, while it is also very flat in the greenish disc snail, but it is clearly (more) visible. In the case of the white disc snail, the mouth can be slightly cross-elliptical, in the case of the greenish disc snail it is rounded.

In the white disc snail the periostracum is colorless, in the greenish disc snail it is yellowish or yellowish green.

Distribution of the species in Europe

Geographical distribution and habitat

The distribution area was probably originally North America. Due to anthropogenic displacement, it is now native to almost all of Europe, albeit only very locally and rarely, especially in gardens, parks, vineyards and also greenhouses. In the east it is also represented in the Caucasus and in the south in northwest Africa.

The animals live deep in loose, moist to dry soil (up to one meter deep). They are therefore mostly only found when larger amounts of soil are processed and sieved, or in the flushing fringes of streams and rivers (Geniste). Usually only the empty housings are found.

Taxonomy

The species was founded in 1889 by Henry Augustus Pilsbry as Zonites singleyanus .

The species was discovered by Kerney et al. (1983) and Schileyko (2002) incorrectly assigned to the genus or subgenus Helicodiscus (Hebetodiscus) Baker, 1929. Both Helicodiscus Morse, 1864 and Hebetodiscus Baker, 1929 would in this case be more recent synonyms of Lucilla Lowe, 1852. Mostly, however, both Helicodiscus Morse, 1864 and Lucilla Lowe, 1852 are regarded as separate genera. Kerney et al. (1983) do not yet separate the two types. The picture seems to show Lucilla singleyana .

Lucilla singleyana (Pilsbry, 1889) is generally accepted as a valid taxon.

Danger

According to Vollrath Wiese, the species is not endangered in Germany. On the other hand, their populations are said to be severely endangered in Austria or endangered in Switzerland.

literature

  • 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 , pp. 137/38.

Individual evidence

  1. ↑ Jürgen H. Jungbluth and Dietrich von Knorre: Trivial names of land and freshwater mollusks in Germany (Gastropoda et Bivalvia). Mollusca, 26 (1): 105-156, Dresden 2008 ISSN  1864-5127 , p. 121.
  2. ↑ a b Michal Horsák, Jozef Šteffek, Tomáš Čejka, Vojen Ložek, Lucie Juřičkova: Occurrence of Lucilla scintilla (RT Lowe, 1852) and Lucilla singleyana (Pilsbry, 1890) in the Czech and Slovak Republics - with remarks how to distinguish these two non-native minute snails. Malacologica Bohemoslovaca, 8: 24-27, 2009 PDF
  3. ↑ Evgenij V. Schikov: Lucilla singleyana (Pilsbry, 1890) and L. scintilla (RT Lowe, 1852) (Gastropoda, Pulmonata, Endodontidae) in the Caucasus and in Russia. Folia Malacologica, 25: 165-174, 2017 doi : 10.12657 / folmal.025.013
  4. ↑ MB Seddon, DT Holyoak: Land gastropoda of NW. Africa. New distributional data and nomenclature. Journal of Conchology, 34: 311-323, 1993 abstract
  5. ^ Henry Augustus Pilsbry: New and little-known American molluscs. Proceedings of the Academy of Natural Sciences of Philadelphia, 41: 81-89, 1889 at Biodiversity Heritage Library, S. 84
  6. ^ A b 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 (p. 202)
  7. ↑ a b AnimalBase: Lucilla singleyana (Pilsbry, 1889) (accessed June 18, 2018)
  8. ↑ Fauna Europaea: Lucilla singleyana (Pilsbry, 1889) (accessed June 18, 2018)
  9. ↑ MolluscaBase: Lucilla singleyana (Pilsbry, 1889) (accessed June 18, 2018)
  10. ^ Vollrath Wiese: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim 2014 ISBN 978-3-494-01551-4 , pp. 157/58.