Dotted Slug - Arion circumscriptus

This slug was until recently separated into two species (Arion circumscriptus and Arion silvaticus). However research, including DNA analysis, has shown that there is a continuum between the two and therefore they should be treated as subspecies (Arion circumscriptus circumscriptus and Arion circumscriptus silvaticus). As the distinction between the two is so blurry, we record all as the main species.

Usually 30-40 mm, greyish centrally and white laterally with a pair of dark-colored longitudinal stripes.There are usually speckly markings on the mantle and the tentacles and head are black in colour, but these features are variable. The pneumostome (breathing pore) occurs in the anterior one-third of the slug's mantle on the right side of the body. In contracted individuals the body is bell-shaped. No keel is present but a row of enlarged pale-coloured tubercles may create an impression that one exists (false keel). The sole is pale coloured, similar to the foot fringe and the mucus  is colourless or occasionally pale yellow.

The subspecies Arion circumscriptus silvaticus is much whiter on the lower flanks, beneath the lateral stripe and has fewer speckles on the mantle.

Arion fasciatus is broadly similar but with yellow tinged flanks below the lateral stripe.

A wide range of habitats, and will tolerate damper conditions than some other species.

All year.

Common though under-recorded due to the similarity with other Arion species.

Fairly common in Leicestershire and Rutland.