Phylogeography of the common pandora Pagellus erythrinus in the central Mediterranean sea. Sympatric mitochondrial lineages and genetic homogeneity

The distribution of the genetic diversity and the population structure of Pagellus erythrinus were analysed using mitochondrial control region sequences and cytochrome b restriction profiles in a total of 128 and 508 individuals, respectively, that were collected from 15 sampling sites in the central Mediterranean Sea and from one site in the Atlantic Ocean. No population genetic structure was detected within the central Mediterranean, and thus, the commonly recognised transition zones in the area do not seem to affect population connectivity. The comparison between the Mediterranean samples and the single Atlantic sample suggests weak differentiation between the two basins. Three mitochondrial lineages were identified, each including individuals from almost every sampling site. The haplotype and nucleotide diversity values, mismatch distribution and demographic parameters indicate that the sympatry of these lineages can be ascribed to a period of isolation followed by genetic divergence, population expansion and secondary contact, all of which are likely to be associated with climatic oscillations that occurred during the middle and late Pleistocene.