New molecular data attest to the absence of cospeciation patterns between <i>Placobdella costata</i> (Fr. Müller, 1846) (Hirudinea) and freshwater turtles (<i>Emys</i> spp.) in Italy

The only Palearctic representative of the leech genus Placobdella Blanchard, 1893 is P. costata, an ectoparasite freshwater turtles. To date, no conclusive evidence about possible presence coevolutionary patterns between this and its turtle hosts available due to paucity DNA sequence data for costata; moreover, comparative host also mostly lacking, making any inferences more difficult. discovery new populations species in northern Italy Sicily allowed us generate novel mitochondrial sequences compare topology resulting phylogenetic trees with phylogeny occurring study area, i.e., Emys orbicularis E. trinacris. branching pattern tree costata not congruent that hosts, thus suggesting lack or cospeciation phenomena these taxa. a might be ascribed different dispersal ability spp. generality leech, as confirmed by occurrence on aquatic turtles belonging Mauremys areas where are rare absent.A single cytochrome c oxidase subunit 1 haplotype was found each region, overall nucleotide diversity very low throughout investigated distribution. This apparent clear phylogeographical unexpected circum-Mediterranean areas, high customary most terrestrial species. Based data, we suggest recent, post-glacial origin studied populations.