Brown slug
| Brown slug | ||||||||||||
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Brown slug ( Arion fuscus ), Czech Republic |
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| Scientific name | ||||||||||||
| Arion fuscus | ||||||||||||
| ( OV Müller , 1774) |
The brown slug ( Arion fuscus ) is a species of slug from the family of slugs (Arionidae), which is subordinated to land snails (Stylommatophora). The species was only recently re-established. Outwardly, it is indistinguishable from the light brown slug ( Arion subfuscus ) ( cryptospecies ).
features
The animal measures about 5 to 7 cm in length when stretched out. The color of the upper side of the body ranges from yellow to dark brown with a back slightly darker than the base color. Two darker, often dark brown, longitudinal bars are clearly set off. The right longitudinal band runs more or less clearly below and above the light-bordered breathing opening. The coat shield is a little lighter than the back of most specimens. It takes up about a third of the body length. The body surface has flat, elongated skin wrinkles. The sole is light gray to white, the back slime is clearly orange. The head and antennae are dark gray.
In the genital system, the sex gland (after opening the mantle) is small, dark and covered by the midgut gland. The hermaphrodite is thin, entwined in the front part. The albumin gland is usually very large and shifted forward into the stomach area. The egg ladder is strongly intertwined. The spermatic duct (vas deferens) is comparatively long and merges into the epiphallus without any clear marking. This gradually thickens and forms a whip-shaped organ that opens into the atrium. This is thickened directly at the mouth of the epiphallus in the atrium. The fallopian tube, on the other hand, is rather short and is somewhat thickened in the area of muscle attachment. The epiphallus and the conductor to the seminal vesicle open side by side into the atrium. The fallopian tube widens between the muscle attachment and the opening into the atrium. In this section, two longitudinal ridges, the so-called ligula, are formed inside the fallopian tube. The spherical seminal vesicle is rather small with a thin seminal vesicle conductor. Its length changes in the course of ontogeny and as the seminal vesicle is filled with sperm. The retractor muscle of the genital mass attaches to the fallopian tube and the base of the seminal vesicle. The atrium is small, barrel-shaped, and often somewhat flattened.
Similar species
Brown slug and light brown slug cannot be distinguished externally. In the reproductive system of the brown slug, the gonad is small, dark and covered by the midgut gland; in the closely related species A. subfuscus it is clearly visible at the edge of the midgut gland and is relatively large and pale. There are also certain differences in the allozymes and in the mitochondrial DNA sequence .
Way of life
Unlike other Arion species, Arion fuscus cannot contract in a semicircle, but instead contracts lengthways. The animals eat fresh plant material, fruits and mushrooms, and occasionally also carrion and vertebrate droppings.
The brown slug is sexually mature at 10 to 11 months, mates and begins to lay eggs. 8 to 12 clutches with 7 to 53 eggs each are laid in the moist soil. The somewhat elongated eggs are 2.5 to 4 mm long and 2 to 3 mm in diameter. The young hatch after a development time of approx. 25 to 40 days. They live to be 12 to 13 months old.
Geographical distribution, occurrence and way of life
The species Arion fuscus is mainly found in Northern, Central and Eastern Europe. The sister species A. subfuscus ( light brown slug ) is widespread in Western Europe (Belgium, France, the Netherlands) . Only in Belgium do both types occur sympatric . They don't cross here. The distribution area of both species is still insufficiently known in detail.
The species occurs in forests, parks, gardens and meadows from the lowlands to the mountains. In the Alps, it rises to 2900 m above sea level.
Taxonomy and nomenclature
The taxon Arion fuscus was established in 1774 by Otto Friedrich Müller as Limax fuscus . The type material is lost, a type locality is not mentioned and the name is therefore also described by some authors as unclear. Welter Schultes considers the name to be a younger homonym, but gives no evidence. The primary homonym Limax fuscus Martin, 1789 (today Bullia martinii ) is younger.
Arion fuscus Müller, 1774 has only recently been separated from Arion subfuscus . Both types cannot be distinguished with certainty from the outside. Therefore many authors treat the two species names as synonyms for practical reasons. Definite distinguishing features of the species are only present in the genital morphology, in the allozymes and in the mitochondrial DNA sequence .
The common name "brown slug" previously referred to both species, which were previously referred to by the scientific name Arion subfuscus (Draparnaud, 1805). After separating into two species, Jungbluth & v. Knorre (2008) the common name Brown Slug on Arion fuscus and created the new common name "Light Brown Slug" for Arion subfuscus . Now that all authors have not followed this idiosyncratic renaming / re-appointment, is the trivial name Arion fuscus in some work sites and Arion fuscus referred, in others with brown slug , however, Arion subfuscus meant.
In the sub-genus subdivision of the genus Arion , which has not been adopted by all authors , the species is assigned to the sub-genus Arion (Mesarion) Hesse, 1926 (together with Arion subfuscus Draparnaud, 1805, Arion brunneus Lehmann, 1862, Arion simrothi Künkel, 1909 and Arion transsylvanus Simroth, 1885 ).
supporting documents
literature
- Klaus Bogon: Land snails biology, ecology, biotope protection. 404 p., Natur Verlag, Augsburg 1990, ISBN 3-89440-002-1
- Rosina Fechter and Gerhard Falkner: molluscs. 287 pp., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 (p. 142) * Rosina Fechter and Gerhard Falkner: Molluscs. 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 and Berlin 1983, ISBN 3-490-17918-8
- Jan Pinceel, Kurt Jordaens, N. van Houten, AJ de Winter and Thierry Backeljau: Molecular and morphological data reveal cryptic taxonomic diversity in the terrestrial slug complex Arion subfuscus / fuscus (Mollusca, Pulmonata, Arionidae) in continental north-west Europe. Biological Journal of the Linnean Society, 83 (1): 23-38, 2004 doi : 10.1111 / j.1095-8312.2004.00368.x
- Jan Pinceel, Kurt Jordaens, Markus Pfenninger and Thierry Backeljau: Rangewide phylogeography of a terrestrial slug in Europe: evidence for Alpine refugia and rapid colonization after the Pleistocene glaciations. Molecular Ecology, 14: 1133-1150, 2005 doi : 10.1111 / j.1365-294X.2005.02479.x
- Jan Pinceel, Kurt Jordaens and Thierry Backeljau: Extreme mtDNA divergences in a terrestrial slug (Gastropoda, Pulmonata, Arionidae): accelerated evolution, allopatric divergence and secondary contact. Journal of Evolutionary Biology, 18 (5): 1264-1280, 2005 doi : 10.1111 / j.1420-9101.2005.00932.x
- Andrzej Wiktor: The nudibranchs of Poland Arionidae, Milacidae, Limacidae (Gastropoda, Stylommatophora) Polska Akademia Zakład Zoologii Systematycznej i Doświadczalnej Monograph Fauny Polski, I, 182 S., Kraków 1973
Individual evidence
- ↑ Jürgen H. Jungbluth, German Malakozoological Society: German names for native snails and mussels (Gastropoda et Bivalvia) (mollbase.de). 294. Arion (Mesarion) fuscus (OF Müller 1774) - Brown slug (syn .: subfuscus part.). Version dated January 15, 2002.
- ↑ 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
- ^ Andrzej Wiktor: Fauna Graeciae. VIII. The slugs of Greece (Arionidae, Milacidae, Limacidae, Agriolimacidae - Gastropoda, Stylommatophora). 240 pp., Natural History Museum of Crete & Hellenic Zoologic Society, Iraklio, Crete, 2001, ISBN 960-367-005-7
- ↑ Otto Friedrich Müller: Vermivm terrestrium et fluviatilium, seu animalium infusoriorum, helminthicorum, et testaceorum, non marinorum, succincta historia. Volume alterum. S. I-XXXVI, 1-214, Havniæ / Copenhagen & Lipsiæ / Leipzig, Heineck & Faber 1774 Online at www.biodiversitylibrary.org (p. 11).
- ↑ Animal Base: Species taxon summary fuscus Müller, 1774 described in Limax
- ^ Thomas Martyn: The universal conchologist: exhibiting the figure of every known shell accurately drawn and painted after nature. London, self-published 1789.