Garlic snail
| Garlic snail | ||||||||||||
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Garlic snail ( Oxychilus alliarius ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Oxychilus alliarius | ||||||||||||
| ( Miller , 1822) |
The garlic gloss snail ( Oxychilus alliarius ) is a land snail from the family of the gloss snail (Oxychilidae); this family belongs to the subordination of land snails (Stylommatophora).
features
The right-hand wound housing is frustoconical and measures 4.5 to 7 mm in diameter and 2.5 to 3.5 mm in height in the adult animal. In the side view, the thread is only slightly raised. It has 4 to 4.5 turns that increase slowly and evenly. Only the last quarter loop can be slightly lowered compared to the winding axis of the previous windings. The top of the turns is slightly arched, the seams are moderately deep. The periphery is well arched, the underside flat. When viewed directly, the mouth is almost rounded, only slightly elliptical to ovoid (apart from the incision of the previous turn). The surface of the mouth is inclined to the coil axis. The mouth edge is straight and sharpened. The umbilicus is relatively wide, it takes up about 1/6 of the total diameter and can be slightly eccentric.
The color of the shell varies from reddish to yellow-brown, sometimes with a slight shade of green. It is translucent, often milky-opaque on the underside in the navel area. With the exception of fine strips of growth, the surface is almost smooth and shiny. The growth stripes are more clearly visible at the seams. They are also very faint, wavy spiral lines.
The body of the animal is blue-gray. The foot is slender and slate gray. The sole is divided into three parts lengthways. The jaw is oxygnath. As a result, the slightly translucent housing also appears significantly darker in living animals. When touched, the animal gives off a strong garlic odor (name!). This smell is u. Z. already perceptible when removing the leaf litter under which the animals live.
In the male tract of the hermaphroditic genital apparatus, the spermatic duct (vas deferens) is quite short. It penetrates apically into the short, U-shaped epiphallus, which is thickly swollen in the first half and thins again in the second half before it enters the penis. In the area of the penis sheath and immediately before it enters the epiphallus, the spermatic duct is connected to the penis by tissue. The epiphallus enters the penis in front of the apex. Directly apically, there is a short but clear blind sac (caecum) on the penis, to which the penis retractor muscle attaches. The penis is twice as long as the epiphallus and only moderately thick (in the upper part only slightly thicker than the swollen part of the epiphallus). There is no or only a very slight constriction between the proximal and distal parts of the penis. Four longitudinal folds are formed in the interior of the penis, which are straight or slightly wavy. In the lower third, the penis is surrounded by a tissue cover (penis cover). In the female part, the free fallopian tube (oviduct) is very short and the vagina is very long. The perivaginal gland surrounds the upper part of the vagina and the basal part of the free fallopian tube, as well as the base of the stem of the spermathec. The stem is very short and initially thickened at the base. The bladder is rounded and reaches the lower part of the egg duct (spermoviduct). The penis and vagina open into a short atrium. The radula is oxygnath, d. H. consists of numerous dagger-shaped teeth. It has 27 to 31 teeth per transverse row.
Similar species
Compared to the cellar snail ( Oxychilus cellerarius ), the shell is rolled up a little closer from the third turn. The seam is a little deeper and the case is significantly smaller. The distinct garlic smell that gave the species its name is not species-specific, as the Swiss gloss snail ( Oxychilus navarricus ) and the great gloss snail ( Oxychilus draparnaudi ) smell slightly of garlic. The garlic snail, however, smells the most intense.
Geographical distribution and habitat
The distribution area is north-west European-Atlantic ( Azores , British Isles , Iceland , Greenland , Scandinavian coastal areas, northern and central Germany, Baltic Sea area), but also some scattered occurrences in Eastern Europe and the Mediterranean region (northern Portugal, Catalonia, northern Greece). The species has been anthropogenic to many other regions, such as North America (e.g. Washington , Hawaii ), New Zealand , South Africa, St. Helena , Juan Fernández Islands , Australia and South America. Giusti and Manganelli, however, question the determination of the New Zealand material.
The species lives under leaves, wood or stones in deciduous forests. It is also occasionally found in gardens and greenhouses. It also tolerates slightly acidic soils.
Way of life
It mainly eats other shell snails (usually only up to its own shell size), small nudibranchs (less than 10 mm in length) and enchytrae , but also fresh parts of plants and carrion. Reproduction takes place in early summer as well as in autumn. The animals are hermaphrodites and fertilize each other. The milky-white, ellipsoidal eggs measure 1.2 to 1.4 mm in length and 0.7 to 0.9 mm in thickness. They have a lime shell. Up to ten eggs are laid per clutch. They reach sexual maturity after one year and are around two years old in total. The smell of garlic given off by the animals is supposed to be a deterrent to possible predators such as B. Hedgehogs act.
The hawaiian garlic snail
Like many other Central European land snails, the garlic snail has now been transported to other regions of the world. In Hawaii, for example, the bright garlic snail, first observed in the 1930s, has now become the most common type of snail and endangers the native species. The spread of the garlic snail is also considered to be a major factor in the extinction of the white-cheeked honeycreeper . This bird, which was previously native to the slopes of Haleakalā on the Hawaiian island of Maui and was only described in 1973, lived mainly on the endemic land snails of the genus Achatinella Hawaiis, which became increasingly rare due to the advance of the garlic snail. The last white-cheeked honeysuckles were observed in 2004.
Taxonomy
The taxon was first described by Johann Samuel Miller in 1822 . The taxon is widely recognized.
The genus Oxychilus is divided by some authors into sub-genera. In this classification, the garlic snail belongs to the subgenus Oxychilus (Ortizius) Forcart, 1957.
Danger
The species is considered endangered in Lower Saxony and Rhineland-Palatinate; it is rare in Bavaria and Austria. In Saxony the species is classified as endangered. It is a kind of advance warning level throughout Germany.
Mollusk of the year
The glossy garlic snail was voted mollusc of the year in 2014, mainly because of the special feature of being able to secrete a slime that smells of garlic. As a carnivorous species, it regulates the populations of herbivorous snails and is therefore an important factor in the ecosystem, including in gardens.
literature
- Klaus Bogon: Land snails biology, ecology, biotope protection. 404 p., Natur Verlag, Augsburg 1990, ISBN 3-89440-002-1 , p. 202/03.
- Rosina Fechter, Gerhard Falkner: Mollusks. 287 p., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 , p. 180.
- 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 , p. 169.
Individual evidence
- ↑ Jürgen H. Jungbluth, Dietrich von Knorre: Trivial names of land and fresh water mollusks in Germany (Gastropoda et Bivalvia). Mollusca, 26 (1): 105-156, Dresden 2008 ISSN 1864-5127 , p. 122.
- ^ Adolf Riedel: Revision of the zonitides of Poland (Gastropoda). Annales Zoologici, 16 (23): 362-464, Posen 1957 PDF , pp. 414-416.
- ↑ a b Falco Giusti, Giuseppe Manganelli: Redescription of two west European Oxychilus species: O. Alliarius (Miller, 1822) and O. Helveticus (Blum, 1881), and notes on the systematics of, Oxychilus Fitzinger, 1833 (Gastropoda: Pulmonata : Zonitidae). Journal of Conchology, 37 (5): 455-476, 2002 PDF (ResearchGate)
- ↑ a b c Vollrath Wiese: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim 2014, ISBN 978-3-494-01551-4 (p. 182)
- ↑ a b c 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 (S. 377)
- ↑ Barry Roth, Timothy A. Pearce: Vitrea contracta (Westerlund) and Other Introduced Land Mollusks in Lynnwood, Washington. The Veliger, 27 (1): 90-92, 1984 PDF (ResearchGate)
- ^ A b Wallace M. Meyer III: Potential impact of an abundant introduced omnivorous land snail, Oxychilus alliarius on native land snails on the Island of Hawaii. Tentacle, 13: 16-17 Cambridge 2005 PDF
- ↑ a b Ewald Frömming: Biology of the Central European Landgastropods. 404 S., Duncker & Humblot, Berlin, 1954, pp. 86-87.
- ↑ a b Vollrath Wiese: The garlic gloss snail Oxychilus alliarius mollusk of the year 2014. PDF (Flyer)
- ^ A b Patrick A. Curry, Norine W. Yeung: Predation on endemic Hawaiian land snails by the invasive snail Oxychilus alliarius. Biodiversity and Conservation, 22 (13-14): 3165-3169, 2013 doi : 10.1007 / s10531-013-0576-3
- ↑ Dominic Couzens: Rare Birds - Survivors, Evolution Losers and the Lost. Haupt Verlag, Bern 2011, ISBN 978-3-258-07629-4 , pp. 144-145
- ^ Johann Samuel Miller: A list of the freshwater and landshells occurring in the environment of Bristol, with observations. Annals of Philosophy (New Series), 3 (17): 376-381, London, 1822 Online at Biodiversity Heritage Library , p. 379.
- ↑ a b AnimalBase: Oxychilus alliarius (Miller, 1822)
- ↑ MolluscaBase: Oxychilus alliarius (JS Miller, 1822)
- ↑ Fauna Europaea: Oxychilus (Ortizius) alliarius (JS Miller, 1822)
- ↑ Katrin Schniebs, Heike Reise, Ulrich Bößneck: Red List of Mollusks of Saxony. State Office for Environment and Geology, Free State of Saxony, 2006. PDF
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