Phylogenetic study of Elona quimperiana (Gastropoda: Elonidae): identification of a new haplogroup

Abstract

The land snail Elona quimperiana is listed in annexes II and IV of the Europe Habitats Directive. In this study, phylogenetic relationships between populations of this protected species from its whole distribution range were reconstructed based on the sequencing of two mtDNA gene fragments (COI and 16S rRNA) and one nDNA gene fragment (ITS2). Haplotype networks were also generated for the COI and 16S rRNA gene fragments. Results yielded three main intraspecific phylogroups, here designated as the lineages Brittany-Spain, Basque, and Navarre-Rioja. This last lineage had not been identified previously. Genetic distances between the three main phylogroups suggest they could have originated by allopatric fragmentation before the Last Glacial Maximum, and then separately evolved in three refugia in the Iberian Peninsula. We here propose that each phylogroup is considered an Evolutionarily Significant Unit. Through extended sampling, we were able to delimit the geographic distribution of all three lineages. Our genetic results support post-glacial colonization of this species from the north-eastern Iberian Peninsula to Brittany in NW-France as proposed previously, and rule out its recent anthropic introduction.