Arion fuscus

Arion fuscus
File:Arion subfuscus-Nl2.jpg
An active individual from the Netherlands
File:Arion subfuscus.jpg
A contracted individual of Arion fuscus from the Czech Republic
Conservation status
NE
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Heterobranchia clade Euthyneura clade Panpulmonata clade Eupulmonata clade Stylommatophora informal group Sigmurethra
Superfamily:	Arionoidea
Family:	Arionidae
Genus:	Arion
Species:	A. fuscus
Binomial name
Arion fuscus (O. F. Müller, 1774)
Synonyms
Arion subfuscus (Draparnaud, 1805)

Arion fuscus, aka "Dusky Arion", is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Arionidae, the roundback slugs.

Arion subfuscus (Draparnaud, 1805) is considered by some authors to be a partial synonym for Arion fuscus. Arion subfuscus (Draparnaud, 1805) and A. fuscus (Müller, 1774) have very similar morphology and have overlapping distributional ranges in northwestern Europe. Arion fuscus is widespread throughout Central, North and East Europe whereas A. subfuscus is restricted to West Europe.(For practical purposes the two are synonyms in Germany and in the Czech Republic.) The two taxa are referred to as the species complex Arion subfuscus/fuscus both members having several evolutionary lineages.They are only separable by alloenzyme analysis and gonad type.

Description

Note. In slugs it is often difficult to establish good criteria for identifying species using external features or internal features, as colouration can be quite variable, and the rather plastic anatomy makes diagnostic anatomical features difficult to establish.

A 50-70 mm. roundback slug. It is brown in colour, ranging from black-brown through olive-brown to orange and bright reddish-orange. Darker lateral bands are present.Dark pigment reaches under the pneumostome from back to front. The foot fringe is pale with thin lines.The sole is uniformly pale/translucent.The tentacles are pale.It does not contract into a bell shape when stimulated. Differs from other Arion species in its yellow-orange body mucus. Genitalia:Atrium about half diameter of spermatheca, spermatheca spherical, oviduct large and swollen like in Arion lusitanicus

Distribution

This species occurs in European countries and islands including:

• Austria
• Bulgaria
• Czech Republic - least concern (LC)
• Germany
• Netherlands
• Poland
• Slovakia
• Great Britain
• Ireland
• China
• and other areas

Habitat

This slug lives under fallen logs and under bark in woodland areas, but it also lives in hedges, gardens, pastures and dunes.

Further reading

• Pinceel J., Joardens K., Van Houtte N., De Winter A.J. & Backeljau T. 2004: 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: 23–38. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1095-8312.2004.00368.x
• Pinceel J., Joardens K., Pfenninger M. & Backeljau T. 2005: Rangewide phylogeography of a terrestrial slug in Europe: evidence for Alpine refugia and rapid colonization after the Pleistocene glaciations. Molecular Ecology 14: 1133–1150. http://www.blackwell-synergy.com/links/doi/10.1111/j.1365-294X.2005.02479.x/abs/
• http://www.springerlink.com/content/7gqg56435443234k/
• "Activity and Ecological Distribution of the Slug, Arion subfuscus (Draparnaud) (Stylommatophora, Arionidae)". JSTOR
• "Relations between forest management and slug assemblages (Gastropoda) of deciduous regrowth forests". doi:10.1016/j.foreco.2006.09.067

External links

• Arion subfuscus at Animalbase taxonomy,short description, distribution, biology,status (threats), images
• Arion subfuscus at Encyclopedia of Life