Prickly litter snail
| Prickly litter snail | ||||||||||||
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Spiny litter snail ( Acanthinula aculeata , OF Müller, 1774) |
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| Scientific name | ||||||||||||
| Acanthinula aculeata | ||||||||||||
| ( OV Müller , 1774) |
The prickly litter snail ( Acanthinula aculeata ), also just prickly snail, is a terrestrial snail species from the family of grass snails (Valloniidae); the family belongs to the subordination of land snails (Stylommatophora).
features
The housing is spherical with a low-tapered thread. It measures approximately 2 × 2 mm and has four whorls. The turns increase regularly and are moderately well rounded on the periphery. The seams are comparatively shallow and the last turn does not fall off the turn axis towards the mouth. The base is slightly flattened, and the navel is open and cylindrical in shape. The embryonic casing has clear spiral lines on the surface. The teleoconch has lamellar, sharp ribs made of periostracum, which are slightly oblique to the axis of the convolutions and which are drawn out on the periphery to triangular, flexible processes (or "thorns"). There are also occasional indistinct spiral lines. The ribs and appendages can therefore only be seen on fresh specimens. They are missing in weathered specimens; the ribs can still be seen, however. In addition to camouflage, the surface is often covered with fecal pills. The mouth is rounded to ovoid, usually wider than it is high and is oblique to the axis of the housing. The mouth edge is only turned over in the spindle area and at the base, initially strongly (at the spindle) then mostly tapering towards the base. The rest of the mouth edge is only very slightly turned over and only slightly thickened on the inside. The case is horn-colored to dark brown.
The soft body is gray on the back, head and tentacles. The foot and sole, on the other hand, are whitish. The radula has 29 elements per transverse row, next to a central tooth 14 elements on each side. There are a total of 87 transverse rows.
Most specimens (9 out of 20 anatomically examined specimens) are aphallic, i.e. H. the male ducts in the hermaphroditic genital apparatus are reduced. However, there are also euphallic specimens in which the male tract has been preserved. The protein gland (albumin gland) is quite large, and the egg duct (spermoviduct) is very long and bloated. The spermatic duct (vas deferens) is unusually short, straight and quickly opens into a short, spindle-shaped epiphallus. Two short, thick, fork-shaped blind processes are formed at the epiphallus / penis transition. The penis is cylindrical and comparatively long. Approximately in the last quarter of the penis there is another, very long, club-shaped appendix with a thick, lower part and a long, thin stem. The retractor muscle forks before it is inserted onto the penile apparatus (i. W. P.). One branch attaches to one of the two processes at the epiphallus / penis transition, the second strand to the lower, very thick part of the long penile appendix. The free fallopian tube is only very short, as the spermathec begins shortly after the spermatic duct branches off. The vagina is moderately long and thick. The stem of the spermathec is thin and moderately long, the bladder small and elongated-ovoid. The bladder is overlapped by the lower end of the albumin gland and the liver.
Similar species
The species is unmistakable in Germany. The closely related beehive ( Spermodea lamellata ) is significantly flattened, has less sharp, but more dense ribs without the appendages ("thorns").
Geographical distribution and habitat
The species is widespread throughout Europe as far as Central Russia. In the north the distribution area extends to northern Scandinavia, in the south to North Africa.
The prickly litter snail lives in moderately moist deciduous forests, in bushes and rows of hedges under leaf litter, old wood in shady habitats, often on calcareous subsoil, more rarely in open habitats or at the foot of limestone rocks under stones. In Liechtenstein it was found up to 1900 m above sea level. However, it is quite rare over 1200 m.
Way of life
Due to the high percentage of aphallic specimens, copulations are rather rare and the animals reproduce mainly through self-fertilization.
Taxonomy
Jungbluth and von Knorre (2008) recommend the use of the common German name Stachelschnecke for this species. This name is very unfortunate because there is also a family of sea snails (Muricidae). Therefore, this suggestion is not followed here and the common name prickly stray snail, which is also widely used in German-language literature, is used.
The taxon was introduced into scientific literature in 1774 by Otto Friedrich Müller as Helix aculeata . Helix aculeata is the type species of the genus Acanthinula Beck, 1847.
Danger
The species is not endangered in Germany. However, stocks in England are declining slightly, as is the case in Bavaria. In Austria, too, the species is potentially endangered, especially due to the destruction of habitats through forest management.
supporting documents
literature
- Klaus Bogon: Land snails biology, ecology, biotope protection. Natur Verlag, Augsburg 1990, ISBN 3-89440-002-1 (p. 142).
- Rosina Fechter and Gerhard Falkner: molluscs. 287 p., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 (p. 148)
- Alexandru V. Grossu: Gastropoda Romaniae 2 Subclasa Pulmonata I Ordo Basommatophora II Ordo Stylommatophora Suprafamiliile: Succinacea, Cochlicopacea, Pupillacea. 443 pp., Bucharest 1987 (pp. 265/6).
- Michael P. Kerney, Robert AD Cameron & Jürgen H. Jungbluth: The land snails of Northern and Central Europe. 384 pp., Paul Parey, Hamburg & Berlin 1983, ISBN 3-490-17918-8 (p. 131)
- 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
- 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 (p. 204)
Individual evidence
- ↑ a b Vollrath Wiese: The land snails of Germany. 352 p., Quelle & Meyer, Wiebelsheim 2014 ISBN 978-3-494-01551-4 (p. 101)
- ^ Hugh Watson: The affinities of Pyramidula, Patulastra, Acanthinula, and Vallonia. 14: 6-30, London 1920 Online at www.biodiversitylibrary.org (p. 11)
- ^ Arthur Edwin Boycott: The genitalia of Acanthinula aculeata. Proceedings of the Malacological Society, 12: 221-226, London 1917 Online at www.biodiversitylibrary.org .
- ↑ 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
- ↑ cf. Fechter and Falkner, p. 148
- ↑ Otto Friedrich Müller: Vermium terrestrium et fluviatilium, seu animalium infusoriorum, helminthicorum, et testaceorum, non marinorum, succincta historia. Volume alterum. SI-XXXVI, 1-214, Heineck & Faber, Copenhagen & Leipzig 1774 Online at www.biodiversitylibrary.org (p. 81/2)
