An ancient lineage of slow worms, genus Anguis (Squamata: Anguidae), survived in the Italian Peninsula

Four species of legless anguid lizard genus Anguis have been currently recognized: A. fragilis from western and central Europe, A. colchica from eastern Europe and western Asia, A. graeca from southern Balkans and A. cephallonica from the Peloponnese. Slow worms from the Italian Peninsula have been considered conspecific with A. fragilis, despite the fact that the region served as an important glacial refugium and a speciation center for European flora and fauna. We used mitochondrial (ND2, tRNAs) and nuclear (PRLR) DNA sequences to investigate the systematic and phylogenetic position of the Italian slow-worm populations and morphological analyses to test for phenotypic differentiation from A. fragilis from other parts of Europe. Our phylogenetic analyses revealed that Italian slow worms form a distinct deeply differentiated mtDNA clade embedded on a basal position within the genus Anguis. In addition, the specimens assigned to this clade bear distinct haplotypes in nuclear gene PRLR and show slight morphological differentiation from A. fragilis. Based on the differentiation in all three independent markers, we propose to assign the Italian clade species level under the name Anguis veronensis, Pollini 1818. Following this taxonomic concept, the newly recognized species is distributed throughout the Italian Peninsula to the Southern Alps and south-eastern France. We hypothesize that the current genetic variability shaped in multiple glacial refugia in the Italian Peninsula, with the firstly separated lineage geographically connected to the region of the Dolomite Mountains