Molecular Updates on the ‘Warty Dorid’ Doris verrucosa Linnaeus, 1758 (Mollusca, Nudibranchia) from the Mediterranean Sea

Basic and applied research reveals the importance of sea slugs as a source of new bioactive molecules or of still little-known intra/intercellular processes, mainly linked to the highly specialised defensive strategies typical of this group of shell-less molluscs. In this context, the nudibranch Doris verrucosa (Gastropoda, Mollusca), commonly known as 'warty dorid', is particularly interesting due to its ability to produce de novo biochemical compounds with pharmacological properties and being the type species of the genus Doris, one of the oldest and richest in species, currently characterised by a troubled systematics. Despite its wide distribution across the Eastern Atlantic Ocean and the Mediterranean Sea, this species has not yet been characterised from a genetic point of view. Considering the importance of assessing species identity to correctly investigate the systematics and to properly unravel potentially useful applications, results from a molecular assessment of such interesting species are provided. Genetic analysis involved species delimitation, phylogeny and haplotype network methods carried out on specimens of D. verrucosa collected from highly anthropised areas of Southern Italy (central Mediterranean Sea). Furthermore, in situ observations allowed us to fill some gaps in knowledge on the ecology and the morphological variability of this species that could be useful for future comparisons.