Light brown slug
| Light brown slug | ||||||||||||
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Light brown slug, Netherlands |
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| Scientific name | ||||||||||||
| Arion subfuscus | ||||||||||||
| ( Draparnaud , 1805) |
The light brown slug ( Arion subfuscus ), also referred to as the brown slug in older works , is a species of slug from the family of slugs (Arionidae), which is subordinate to the land slugs (Stylommatophora). In the older conception of the species, Arion subfuscus was a species complex that is now divided into three types ( Arion subfuscus , Arion fuscus and Arion transsylvanus ). There may be other species hidden in this species complex.
features
The animal is stretched out to about 7.5 cm long. The top of the body is ocher-yellow, orange-brown, red-brown, dark-brown to even gray with a slightly darker back and a darker, mostly dark-brown longitudinal band on both sides. On the right side, this runs more or less clearly below and above the light-edged breathing opening. Usually the bandages are sharper towards the foot than towards the back. A slightly lighter line runs above the dark band. The sole is cream to white. The sole slime is colorless, whereas the back slime is clearly orange in color.
Young animals are usually drawn more sharply or with more contrast than the adult animals. A light zone runs over the bandages, the back is dark brown. In all animals, the coat shield is usually a little lighter than the back. This is covered with fine, elongated wrinkles.
In the genital apparatus, the sex gland is clearly visible (after opening the mantle) at the edge of the midgut gland. She is relatively tall and pale. The hermaphroditic duct is thin and somewhat 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. There is no penis in the reproductive system. The spermatic duct (vas deferens) is comparatively long and merges into the epiphallus without any clear marking. The epiphallus opens ventrally directly into the atrium. The epiphallus is slightly longer than the vas deferens. In contrast, the conductor to the seminal vesicle opens dorsally into the atrium. A fanned out retractor muscle to retract the genital mass is attached to the seminal vesicle duct and the rear part of the free fallopian tube. Retentor muscles attach to the anterior part of the free fallopian tube and near the confluence of the epiphallus with the atrium. The spermatophore is 17 mm long with a blunt-ended "head" and a thread-like "tail".
Similar species
The light brown slug does not differ externally from the brown slug ( Arion fuscus ). In the genital system, the gonad is clearly visible at the edge of the midgut gland after opening the mantle. She is relatively tall and pale. In contrast, the gonad of the closely related species A. fuscus is small, dark, and obscured by the midgut gland. The two species are also characterized by very clear differences in allozyme and mtDNA . In the few areas where they appear together, they do not cross each other.
Geographical distribution, occurrence and way of life
The species is common in Western Europe. The species is generally more common in forests, but also in parks, gardens and meadows. In the forest, they often climb up the trunks of trees in wet weather. They feed on plant matter and fungi. However, the exact distribution is unclear, as it was only recently recognized that Arion subfuscus i. w. S. two or three species had been united. In northern, central and southern Europe, the sister species A. fuscus seems to occur. The species has also been introduced to North America. So far only the S1 haplotype has been detected there.
Reproduction
Copulation takes at least two hours. During the observation, the two partners had already taken a c-shaped curved posture, with the head of one partner following the tail of the other partner and thus forming a circle. The right-hand side of each pointed towards the inside of the circle, the tentacles withdrawn. Then the atria are everted and together form a spherical white mass that almost fills the interior of the circle. Then two bottle necks are formed from this mass near the genitals. In this phase the spermatophores are exchanged. Then the genital mass retreats back into the genital openings and the tips of the spermatophores are briefly visible in the genital openings. Then the more active partner turns out the antennae and crawls away, while the other remains in place for a while.
Taxonomy and nomenclature
The taxon was first described by Jacques Philippe Raymond Draparnaud as "Limace brunâtre Limax subfuscus ". The type locality is in the Tarn department in the Occitanie region ( Montagne Noire , France). Garrido et al. (1995) re-described topotype material and determined a neotype .
So far, Arion subfuscus was a species complex that included several species. One species that has recently been separated from Arion subfuscus is Arion fuscus Müller, 1774 ( brown slug ). Pinceel et al. a. (2004) and Pinceel et al. a. (2005) also separated 5 haplogroups (mitochondrial DNA lines), which they named S1-S5 without naming them formally.
Arion transsylvanus Simroth, 1885 is another species from the Arion fuscus / subfuscus complex that was recently established as an independent species. Presumably other species are hidden in the Arion fuscus / subfuscus species complex .
A form with a black-brown back and almost missing side bands, which was previously classified as A. subfuscus , is separated by most authors as a separate species Arion brunneus (Lehmann, 1862). More recent works only see a brown color variant in it, which occurs in different ways. So far it is unclear to which species the A. brunneus type material belongs.
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 fuscus Müller, 1774, Arion brunneus Lehmann, 1862, Arion transsylvanus Simroth, 1885 and Arion simrothi Künkel, 1909 ).
The common name brown slug previously referred to the species complex that had been given the scientific name Arion subfuscus (Draparnaud, 1805). After separating into two species, Jungbluth & v. Knorre (2008) changed the common name Brown Slug to Arion fuscus and created the new common name Light Brown Slug for Arion subfuscus . Since not all authors have followed this very idiosyncratic renaming / renaming, the common name brown slug is used in some works and websites to refer to Arion fuscus , in other works, especially older works, brown slug means Arion subfuscus .
supporting documents
literature
- Rosina Fechter and Gerhard Falkner: molluscs. 287 pp., Munich, Mosaik-Verlag 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3
- Carlos Garrido, José Castillejo, Javier Iglesias: The Arion subfuscus complex in the eastern part of the Iberian Peninsula with redescription of Arion subfuscus (Draparnaud, 1805). Archive for Molluscology, 124: 103-118, Frankfurt / M.
- 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
- Jürgen H. Jungbluth and Dietrich von Knorre: Common names of land and freshwater mollusks in Germany (Gastropoda et Bivalvia). Mollusca, 26 (1): 105-156, Dresden 2008 ISSN 1864-5127
- Jan Pinceel, Kurt Jordaens, Natalie van Houtte, 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, Oxford 2004 ISSN 0024-4066 doi : 10.1111 / j.1095-8312.2004.00368.x
- Jan Pinceel, Kurt Jordaens, Natalie Van Houtte, Gary Benson and Thierry Backeljau: Population genetics and identity of an introduced terrestrial slug: Arion subfuscus sl in the north-east USA (Gastropoda, Pulmonata, Arionidae). Genetica, 125: 155-171 2005 doi : 10.1007 / s10709-005-5816-3
Individual evidence
- ^ Jacques Philippe Raymond Draparnaud: Histoire naturelle des mollusques terrestres et fluviatiles de la France. Ouvrage posthumous. Avec XIII planches. I – VIII, 1–134, plates 1–13, Paris & Montpellier, Plassan & Renaud Online at www.biodiversitylibrary.com (p. 125) and plate 9, Fig . 8 .
- ^ A b Kurt Jordaens, Jan Pinceel, Natalie Van Houtte, K. Breugelmans & Thierry Backeljau: Arion transsylvanus (Mollusca, Pulmonata, Arionidae): rediscovery of a cryptic species. Zoologica Scripta, 39: 343-362 doi : 10.1111 / j.1463-6409.2010.00425.x
- ↑ Arion (Mesarion) brunneus. In: Molluscs of central Europe. Retrieved October 16, 2008 .
- ↑ Fauna Europaea: Arion (Mesarion) subfuscus (Draparnaud 1805)
