Leiostyla

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Leiostyla
Leiostyla anglica

Leiostyla anglica

Systematics
Superordinate : Heterobranchia
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Superfamily : Pupilloidea
Family : Lauriidae
Genre : Leiostyla
Scientific name
Leiostyla
Lowe , 1852

Leiostyla is a living on the land snails - genus of the family lauriidae that the terrestrial snails is provided (gastropod).

features

The egg-shaped cases are 2.4 to 5 mm high and 1.8 to 2.5 mm wide. The apex is rounded flat. There are five to six turns that are slightly curved. The last turn is slightly rising just before the mouth. The horn-colored shell is relatively thin and translucent. The embryonic convolutions are smooth, the postembryonic convolutions are covered with radial folds that weaken towards the mouth. The mouth plane is approximately vertical to the longitudinal axis of the housing. The mouth is approximately crescent-shaped to U-shaped with a slightly flattened upper palate rim. The mouth rim is bent and thickened with lips. The points of attachment of the mouth edge to the previous turn are far apart. The parietal callus is weak. The mouth reinforcement consists of two parietal and one almost horizontal columellar lamella, as well as a basal tooth and a palatal fold (palatal fold). The palatal fold extends deep into the mouth, but the posterior end is usually visible in the frontal view of the mouth. Another lower callus is formed in the upper palate area. The cylindrical umbilicus is comparatively wide open.

In the male tract of the sexual apparatus, the thin vas deferens later branch off from the egg vas deferens (spermoviduct) and opens apically into the very long epiphallus . This swells very quickly at the confluence of the spermatic duct, only to decrease again to less than half the diameter after about a quarter of the epiphallus length. A moderately long, thin, worm-shaped blind sac (penis caecum) attaches to the epiphallus / penis transition. After that, the penis first increases in thickness and then decreases again until the penile appendix branches off. After the branching off of the penile appendix, the penis swells again to form a spherical shape, only to decrease again to merge into the atrium. Overall, the epiphallus is almost twice as long as the penis. The penile appendix is ​​extremely long, with a comparatively long, thickened basal part, a long, tortuous, thread-like central part and a slightly shorter, strongly thickened end part. In the female genital tract, the free fallopian tube is much longer than the short vagina. The stem of the sperm library is very long and strongly thickened in the upper part. The bladder extends to the protein gland and the sex gland.

Geographical distribution

The representatives of the genus Leiostyla occur in Madeira , the Azores and the Canary Islands as well as in Western Europe and North Africa.

Taxonomy

The taxon Leiostyla was proposed as a subgenus of Pupa by Richard Thomas Lowe in 1852 . He added six species to his new subgenus: Pupa vincta Lowe, 1852, Pupa irrigua Lowe, 1852, Pupa laurinea Lowe, 1852, Pupa laevigata Lowe, 1852 and Pupa macilenta Lowe, 1852. In 1854 he designated Leiostyla anglica as a type. This determination of the type species is invalid because this species is not listed among the six species in the first description of the genus. Only Henry Augustus Pilsbry published in 1922 with Pupa vincta Lowe, in 1852 a valid type species definition in the sense of zoological nomenclature. He also treated Leiostyla as a sub-genus, albeit the genus Lauria Gray, 1840. Today the genus is generally recognized as an independent genus (Schileyko, Welter-Schultes, Fauna Europaea).

The list is likely to be incomplete as a newer revision of the genus is missing. Some types, e.g. B. from the wider Caucasus, which were previously placed under the genus Leiostyla , are now assigned to other genera.

supporting documents

literature

  • Anatolij A. Schileyko: Treatise on Recent terrestrial pulmonate molluscs, Part 1. Achatinellidae, Amastridae, Orculidae, Strobilopsidae, Spelaeodiscidae, Valloniidae, Cochlicopidae, Pupillidae, Chondrinidae, Pyramidulidae. Ruthenica, Supplement 2 (1) : 1-126, Moscow 1998 ISSN  0136-0027 (p. 83)
  • Henry Augustus Pilsbry: Manual of Conchology. Second Series: Pulmonata. Vol. 27. Pupillidæ (Orculinæ, Pagodulinæ, Acanthinulinæ, etc.). Pp. I-IV, 1-369, Philadelphia, 1922–1926 (1922) online at www.archive.org (p. 67)
  • 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., Planet Poster Ed., Göttingen 2012, ISBN 3-933922-75-5 , ISBN 978-3-933922-75-5 (S. 133)

Individual evidence

  1. ^ Richard Thomas Lowe: Brief diagnostic notices of new Maderan land shells. Annals and Magazine of Natural History, 2nd series, 9 (50): 112-120, 275-279, London [online at www.biodiversitylibrary.org].
  2. ↑ Richard Thomas Lowe: Catalogus molluscorum pneumonatorum insularum Maderensium: or a list of all the land and freshwater shells, recent and fossil, of the Madeiran islands: arranged in groups according to their natural affinities; with diagnoses of the groups, and of the new or hitherto imperfectly defined species. Proceedings of the Zoological Society of London, 22: 161-218, London 1855 ("1854") online at www.biodiversitylibrary.org (p. 208).
  3. ↑ Fauna Europaea

Web links

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