Slender dwarf horn snail
| Slender dwarf horn snail | ||||||||||||
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Carychium tridentatum |
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| Scientific name | ||||||||||||
| Carychium tridentatum | ||||||||||||
| ( Risso , 1826) |
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The slender dwarf horn snail ( Carychium tridentatum ), also slender dwarf snail, is a very small species of snail from the family of the Carychiidae in the order of the lung snails (Pulmonata).
features
The very small, elongated egg-shaped case measures 1.8 to 2.3 mm in height and 0.8 to 0.9 mm in width. The height-width index is> 2. There are five whorls that are strongly curved. The surface shows regular and comparatively clear growth stripes. However, these can only be seen with a magnifying glass; the housing appears smooth to the naked eye. The shells of living animals are colorless and translucent.
The mouth is slightly oblique to the coil axis. The hem of the mouth is turned outwards and thickened by a distinct lip on the inside. A low but wide tooth protrudes from the outer lip into the mouth. A spindle lamella and a parietal lamella are formed on the inner lip. The parietal lamella has the shape of an irregularly curved ridge that is doubly curved in profile. The height / width ratio, the intensity of the stripes and the course of the folds are somewhat variable.
If the animals are well fed, the golden yellow midgut gland can be seen clearly.
Similar species
The shell is on average somewhat larger, but somewhat narrower than that of the bellied pygmy snail ( Carychium minimum ). This means that the case is slimmer and more conical, the five passages are slightly less curved. Usually it is also more clearly striped. As a rule, the slim dwarf horn snail colonizes somewhat drier biotopes than the bellied dwarf horn snail. But there are definitely places where both types occur together. Then there are specimens that cannot be clearly identified morphologically.
Geographical distribution and habitat
The slender dwarf horn snail is widespread in almost all of Europe, in the north the area extends beyond 60 ° latitude. In the east the distribution area extends over Asia Minor to the Caucasus, in the south to North Africa.
The species is found in many habitats, e.g. B. in constantly moist layers of leaf litter in forests, on moist meadows and heavily overgrown locations under stones and scree slopes. It does not require as moist locations as the closely related bellied dwarf horn snail. When it is dry, it withdraws between damp cracks and crevices and only comes out again when the weather is damp. In Switzerland it rises to 2200 m above sea level. In northern Scandinavia, on the northern edge of the distribution area, however, it is limited to the coastal regions.
Way of life
The animals are hermaphrodites, but one-sided mating takes place. The male sexual organs are only developed in July / August, after which they regress again. The male sexual opening is on the head, in front of the antennae on the right side of the body. The female genital opening, however, is under the edge of the coat. The copulation (s) take place in July to August. The oval eggs with a transparent shell measure 0.41 × 0.32 mm. In total, only five to six eggs, which are very large in relation to body size, are deposited individually in the sludge. The young hatch in the spring with a housing that is already 0.4 mm high. They grow until November and can then be 1.2 to 1.5 mm in size. The young seem to have a high chance of survival. 60% of them survive the first year. Overall, the animals will probably be three years old.
Taxonomy
The taxon was first described in 1826 by Joseph Antoine Risso as Saraphia tridentata . It is the type species of the genus Saraphia Risso, monotyped in 1826 . Saraphia Risso, 1826 is now treated by some authors as a subgenus of Carychium , but mostly it is considered a synonym .
Danger
The species is not endangered in Germany.
supporting documents
literature
- Bank, Ruud A. & Edmund Gittenberger 1985: Notes on Azorean and European Carychium species (Gastropoda Basommatophora: Ellobiidae). Basteria, 49: 85-100, Leiden
- Bogon, Klaus 1990: Land snails biology, ecology, biotope protection. 404 p., Natur Verlag, Augsburg ISBN 3-89440-002-1 (p. 80/1)
- Fechter, Rosina & Gerhard Falkner 1990: Mollusks. 287 pp., Mosaik-Verlag, Munich (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 (p. 126)
- Kerney, Michael P., RAD Cameron & Jürgen H. Jungbluth 1983: The land snails of Northern and Central Europe. 384 pp., Paul Parey, Hamburg & Berlin ISBN 3-490-17918-8 (p. 75)
Individual evidence
- ↑ Bogon (1990: p. 84)
- ↑ Kerney et al. (1983: pp. 74/5)
- ↑ Doll, W. 1982: Observations on the way of life and reproduction of Carychium tridentatum Risso in the Upper Rhine region (Pulmonata: Ellobiidae). Archives for Molluscology, 112 (1/6): 1-8.
- ↑ Risso, Josephe Antoine 1826: Histoire naturelle des principales productions de l'Europe méridionale et particulièrement de celles des environs de Nice et des Alpes Maritimes. Tome quatrième. SI-VII, pp. 1-439, plates 1-12, Paris, Levrault (p. 26).
- ^ Wiese, Vollrath 2014: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim ISBN 978-3-494-01551-4 (p. 41)
