DEROCERAS JURANUM - A MENDELIAN COLOR MORPH OF D-RODNAE (GASTROPODA, AGRIOLIMACIDAE)

The terrestrial slug Deroceras juranum Wuthrich, 1993 (Gastropoda: Agr iolimacidae) has been described as an endemic species of the Swiss Jur a Mountains (Switzerland) where it occurs at high altitudes. The speci es description was mainly based on its characteristic blackish-violet body colour. Breeding experiments and comparative studies of the genit al anatomy and mating behaviour indicate that D.juranum is nothing but a colour morph of the usually cream-coloured D. rodnae Grossu & Lupu, 1965. The body colour seems to be coded by a single locus with two al leles, of which violet is dominant over cream. Topographical colour va riation has also been observed in arionid slugs. Its possible biologic al (i.e. selective?) meaning is discussed. The slugs are able to repro duce uniparentally with their offspring showing recombination.