Arion circumscriptus

Grey Slug (Arion circumscriptus )

The Grey Slug (Arion circumscriptus ) is a nudibranch of the family of slugs ( Arionidae ) that is provided to the subordination of terrestrial snails ( gastropod ). The type is difficult to distinguish two closely related species, since the coloring of the species is very variable. Recent studies doubt the independence of the kind.


The Grey Slug measures stretched about 3 to 5 cm. The back is steel-gray to bluish - gray. The lateral strip ( binding) are relatively wide and usually colored a little darker than the back. They are separated from the back by a bright stripe. However, this can be almost absent. For the sole way followed by another light strip. The sole is white. On the mantle shield, the same pattern is observed, the strips are offset with respect to the stripes on the foot. The breathing hole is usually enclosed wholly or partly by the side strips.

Occurrence, lifestyle and dissemination

The species lives in deciduous forests often on fallen wood. They feed mainly on fungi and fungal mycelia. It is distributed in Central and Western Europe. In the north, it occurs to southern Scandinavia. The Grey Slug has since been deported as many other originally European slug species to North America.


The independence of the kind was provided by Sofie Geenen and co-authors in question in 2006. They found in the three species Arion fasciatus ( Nilsson, 1823) ( Gelbstreifige slug ), Arion silvaticus Lohmander, 1937 (forest slug ) and Arion circumscriptus Johnston, 1828 ( Grey Slug ) neither consistent features in the genital anatomy still sufficient differences in DNA investigations. The differences in coloration they lead to the establishment of color options back through long periods of self-fertilization. If the interpretation of their results confirm, would Arion silvaticus Lohmander, 1937 and Arion circumscriptus Johnston, 1828 junior synonyms of Arion fasciatus ( Nilsson, 1823). All three species are found in which some authors did not use sub-genus Arion ( Arion Carin ) Hesse, 1926. In the original conception as an independent species had Arion circumscriptus following synonyms: Arion ambiguus Pollonera, 1889, Arion bourguignati Mabille, 1868, Arion miser Pollonera, 1887 and Arion subcarinatus Pollonera, 1885.