Mitochondrial DNA structure of the Iberian populations of the white-clawed crayfish, Austropotamobius italicus italicus (Faxon, 1914).

This study describes the mitochondrial structure of the Iberian population of the white-clawed crayfish Austropotamobius italicus under a phylogeographyc context and considering the genetic variation of the entire taxon distributed in the southern part of Europe. Current sub-specific hypotheses were only partially supported, and a genetic structure related to climatic events is postulated as the main factor explaining its variation. Due to a more extensive sampling and sequencing strategy, the two different mitochondrial lineages of the taxon were found in the Iberian Peninsula, and haplotype variation of populations was observed in a considerable extent regarding that reported in previous studies from other parts of its distribution range. This evidence, together with the timing of Pleistocene expansion events for the Iberian populations (∼10,772–20,004 YBP) as well as an estimated splitting time from Italian populations previous to the last glacial maximum (T=34,858years) suggest that the presence of A. italicus in the Iberian Peninsula could be explained by a combination of contrasting dispersal histories and a complex biogeographic scenario. We propose that although possible, human translocations may not be the only cause to explain the complex distribution patterns of species strongly affected by recent climatic events.