Helicella

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Helicella
Common heather snail (Helicella itala)

Common heather snail ( Helicella itala )

Systematics
Subordination : Helicina
Superfamily : Helicoidea
Family : Geomitridae
Subfamily : Helicellinae
Tribe : Helicellini
Genre : Helicella
Scientific name
Helicella
A. É. de Férussac , 1821

Helicella is a genus of snails from the family Geomitridae in the order of thepulmonate snails (Pulmonata).

features

The cases are medium-sized (6 to 9 mm high, 12 to 25 mm wide) and mostly flattened. They have five to six moderately curved to slightly flattened turns. The last turn can be rounded, but also slightly keeled or edged. It does not descend, or only very little, towards the mouth. The mouth is rounded to elliptical with sharp edges. The navel is rather wide and funnel-shaped.

The mostly whitish, also brownish skin is mostly firm and opaque. The drawing consists of brown bands of different widths, which can dissolve in rows of spots, fade or even be missing completely. The embryonic convolutions are smooth, the juvenile and adult convolutions are only weakly sculpted, usually only provided with growth strips.

The animals are hermaphrodites. In the male tract of the sexual apparatus, the spermatic duct (vas deferens) penetrates the epiphallus at an acute angle. The flagellum is slender and two to three times shorter than the cylindrical epiphallus. The penis is spindle-shaped with a large brim and a central pore; the pore is surrounded by two to three short lobes. The penis sheath is comparatively thin. The two arrow bags are relatively large and sit on the vagina. Both arrow sacks open into protuberances in the vagina. The two glandulae mucosae each have one to four arms. The free fallopian tube is two to four times shorter than the vagina. The comparatively long stem of the spermathec is sub-cylindrical, the bladder rests on the upper half of the egg ladder.

Geographical distribution and habitat

The species of the genus Helicella occur in western, central and southern Europe. Helicella itala was abducted to Australia in the second half of the 19th century.

The Helicella species mainly live in dry, warm habitats, where they are often found in large numbers. In summer when it is very dry, they often climb grass and herbaceous plants, close their housing with a diaphragm and rest in summer.

Taxonomy

The taxon was established in 1821 by André Étienne d'Audebert de Férussac . Since there were different concepts of the genus in the past, due to different type species definitions, the Commission for Zoological Nomenclature determined Helix itala to be the type species. Francisco Welter-Schultes puts the following species in the genus Helicella :

Helicella is the type genus of the subfamily Helicellinae Ihering, 1909.

supporting documents

literature

  • Anatolij A. Schileyko: Treatise on Recent terrestrial pulmonate molluscs, Part 14 Helicodontidae, Ciliellidae, Hygromiidae. Ruthenica, Supplement 2 (14): 1907-2047, Moscow 2006 ISSN  0136-0027 (publication date corrected in vol. 15, p. 2115) (p. 1986)
  • 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

Individual evidence

  1. ↑ Harold E. Quick: Emigrant British Sbails. Proceedings of the Malacological Society of London, 181-189, 1952 PDF
  2. ↑ André Étienne d'Audebert de Férussac: Tableaux systématiques des animaux mollusques classés en familles naturelles, dans lesquels on a établi la concordance de tous les systèmes; suivis d'un prodrome général pour tous les mollusques terrestres ou fluviatiles, vivants ou fossiles. I-XLVII, 1-27, 1-110, Paris & London, Bertrand & Sowerby, 1821-22 Online at www.biodiversitylibrary.org (p. 24 in quarto).
  3. ↑ ICZN 1987: Opinion 431 PDF

On-line

Web links

Commons : Helicella  - collection of images, videos and audio files