Ground keel cone
| Ground keel cone | ||||||||||||
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Ground keel cone ( Tandonia budapestensis ) |
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| Scientific name | ||||||||||||
| Tandonia budapestensis | ||||||||||||
| ( Hazay , 1881) |
The ground keel snail ( Tandonia budapestensis ), also ground keel slug, is a nudibranch from the family of the keel snails (Milacidae) in the suborder of the land snails (Stylommatophora).
features
The animal is stretched out to about 7 cm long. When stretched, the animal is very slender, the width gradually decreases towards the tail. The coat takes up a little less than 1/3 of the total length. The breathing opening is in the back of the coat on the right side. It is surrounded by a dark border. The body color varies from yellowish to brownish to gray. Often there is a net-like pattern with numerous black spots, so that such animals look almost uniformly black-brown. The sides of the body are a little lighter, here the dots usually disappear. Sometimes there are also dark side stripes. As a rule, the black spots are concentrated in the longitudinal furrows between the (longitudinal) wrinkles. The coat is also dotted with weak to moderate side stripes. They walk around the horseshoe-shaped shallow pit. The clear keel is yellow to orange in color (without dots) and reaches up to the coat shield. The narrow sole is whitish, yellowish to brownish-yellowish usually with a darker central stripe, or can be a little darker overall. A three-way division in the longitudinal direction is clearly visible. The mucus is colorless and viscous. If the animal is irritated, on the other hand, a slightly yellowish, thinner mucus is secreted. The head and tentacles are blackish and stand out very clearly, especially in lighter colored animals. mini | The trisection of the sole in the longitudinal direction can be clearly seen. The aragonitic shell plate in the mantle is elongated, uniform, but symmetrical. The embryonic part in the back half does not stand out.
The hermaphrodite is elongated, the hermaphroditic duct long and comparatively thick. The albumin gland (protein gland) is also divided elongated and lobed. In the male tract of the sexual apparatus, the spermatic duct opens somewhat laterally on the apex of the epiphallus. The epiphallus is thick and club-shaped; the diameter widens slightly towards the rear end. The penis is spherical to slightly conical; here, too, the rear end is thicker. The transition epiphallus / penis is marked by a marked change in thickness and by the lateral attachment of the penile retractor muscle. The epiphallus is usually about twice as long as the penis. A simple papilla sits inside the penis. The sperm library has only a short, thick stem. The bladder is relatively large and ovoid, rounded at the top. The free fallopian tube is very long, while the vagina is short and the atrium is short. A stimulator is missing. The accessory glands are bilobed and are connected to the transition area atrium / vagina by thin, tubular conductors, where they open into the vagina. The spermatophores are thin, up to 16 mm long and almost completely covered on the outside with short thorn-shaped processes.
Geographical distribution and habitat
Presumably, the range of the species was originally limited to the southeastern Alps, the northern Balkans, Hungary and Romania . Today the species occurs very locally due to human displacement and mostly in cultivated land from the British Isles , across Western and Central Europe to Kaliningrad and the Ukraine . In the south from the Apennine Peninsula , across Greece to Turkey . It prefers warmer areas and is therefore absent in the low mountain ranges of Central Europe. In Austria the highest occurrence is around 530 m above sea level. In the south of Bulgaria it is usually found between 300 and 1000 m above sea level, but locally also up to 2,200 m.
The species is anthropochoric (carried away by humans) also in Iceland, North America, and New Zealand .
The animals are found in Central Europe mainly in parks, gardens and fields (synanthropic). The species is now widespread in Western and Central Europe.
Way of life
The species needs a relatively high level of moisture and is nocturnal. The animals rarely appear during the day, even in rainy weather. During the day or during longer dry periods, the animals dig up to several tens of centimeters deep in the ground. The animals prefer rather heavy soils.
Reproduction
The animals are hermaphrodites and fertilize each other. The mating takes place in Central Europe in spring and autumn. In the British Isles, copulations were observed from November to January. Copulation usually begins at night and can last up to 15 hours and more. During copulation, the everted genitals of both partners can be seen. Several clutches with up to 30 eggs (20 eggs) are laid in the ground. From the eggs laid in autumn (or winter), the young hatch in April / May. Sexual maturity is then already reached in autumn. In Central Europe, adult and adolescent animals that are not yet sexually mature can be observed hibernating in autumn. The eggs laid in autumn also overwinter in the egg phase.
Others
The skin or the secreted mucus of the ground keel is very likely poisonous. Experiments with the snail beetle Pterostichus melanarius (family Carabidae) showed that most of the animals that had eaten on freshly killed ground keel cones died within a few days. The yellow to orange keel could thus be interpreted as a warning color (comparable to the yellow-black pattern in wasps).
Taxonomy
The taxon was established in 1880 by Julius Hazay as Amalia budapestensis . Today it is uniformly placed in the genus Tandonia Lessona & Pollonera, 1882. The species has several synonyms : Amalia ibiniensis Kimakowicz, 1884, Limax gracilis Leydig, 1876 and Milax valachicus Grossu & Lupu 1961.
Danger
Since the species is not originally native to Germany, it is not included in the Red List of internal mollusks, snails (Gastropoda) and mussels (Bivalvia) in Germany (2012).
literature
- Rosina Fechter, Gerhard Falkner: Mollusks. 287 pp., Munich, Mosaik-Verlag 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 .
- 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 .
- Andrzej Wiktor: The Polish Nudibranchs. Monograph Fauny Polski, Polska Akademia Nauk Zakład Zoologii Systematycznej i Doświadczalnej, Warsaw / Kraków 1973, here pp. 54-56.
- Andrzej Wiktor: The slugs of the former Yugoslavia (Gastropoda terrestria nuda - Arionidae, Milacidae, Limacidae, Agriolimacidae). Annales Zoologici 46 (1-2): 1-110, Warsaw 1996, here pp. 25-28.
On-line
Individual evidence
- ↑ a b Julius Hazay: The molluscan fauna of Budapest. Malakozoologische Blätter (New Series) 3 ("1881"): 1-69, 160-183, Plates I-IX [= 1-9]. Cassel / Kassel, 1880, here p. 37, plate 1, fig. 1.
- ↑ 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 (p. 439)
- ^ M. Zeki Yildirim and Ümit Kebapci: Slugs (Gastropoda: Pulmonata) of the Lakes Region (Göller Bölgesi) in Turkey. Turkish Journal of Zoology, 28: 155-160, Ankara 2004.
- ↑ L. Dvořák, T. Čejka & M. Horsák: Present knowledge of distribution of Tandonia budapestensis (Hazay, 1881) in the Czech and Slovak Republics (Gastropoda: Milacidae). Malalacological Newsletter, 21: 37-43, 2003 PDF
- ^ H. Reise, JMC Hutchinspn and DG Robinson: Two introduced pest slugs: Tandonia budapestensis new to the Americas, and Deroceras panormitanum new to the Eastern USA. Veliger, 48: 110-115, Berkeley 2005
- ^ New Zealand Mollusca
- ↑ WOC Symondson: Does Tandonia budapestensis (Mollusca: Pulmonata) contain toxins? Evidence from feeding trials with the slug predator Pterostichus melanarius (Coleoptera: Carabidae). In: Journal of Molluscan Studies. 63: 541-545 London 1997
- ↑ MolluscaBase: Tandonia budapestensis (Hazay, 1880)
- ↑ a b Vollrath Wiese: The land snails of Germany. 352 pp., Quelle & Meyer, Wiebelsheim 2014 ISBN 978-3-494-01551-4 (p. 201)