First records of the true Sicilian slug Deroceras panormitanum (Eupulmonata: Agriolimacidae) in France and mitochondrial sequences of three additional species of the genus Deroceras

The genus Deroceras (Eupulmonata: Agriolimacidae) is the richest genus of slugs in terms of described species and as such represents a challenge for taxonomic knowledge, endemic species conservation and invasive species management. Until now, 15 species of Deroceras have been recorded in mainland France. We report for the first time in France the presence of the true Sicilian slug, Deroceras panormitanum (Lessona et Pollonera, 1882), at three sites. This name had formerly long been used to designate specimens of the tramp slug, Deroceras invadens Reise, Hutchinson, Schunack et Schlitt, 2011. In this study, 72 specimens of the genus Deroceras collected from 23 French sites were analysed based on anatomical and/or molecular criteria (barcoding fragments of the mitochondrial cytochrome c oxidase subunit I gene and 16S ribosomal RNA gene). The sequences obtained were placed in molecular phylogenies including reference sequences from the literature. Four species were recorded: D. panormitanum, D. invadens, D. reticulatum (O. F. Müller, 1774) and D. agreste (Linnaeus, 1758). Incongruence between anatomy and mitochondrial sequences in some specimens suggested hybridisation between D. reticulatum and D. agreste.