Insights into the molecular phylogeny and historical biogeography of the white-clawed crayfish (Decapoda, Astacidae)

[Display omitted] •Evolutionary history of the white-clawed crayfish (WCC) from entire distribution range was evaluated.•Results of species delimitation analyses indicate at least four mtDNA groups in WCC as primary species hypotheses.•nuDNA sequences show no significant variation, favouring single secondary species hypothesis, and mito-nuclear discordance.•We provide ancestral ranges and divergence time estimates that could explain current distribution and diversity.•The most recent common ancestor of the mtDNA groups most likely originated from Dalmatia ecoregion (eastern Adriatic coast). In this study, the evolutionary history of the white-clawed crayfish (WCC) was evaluated using large-scale datasets comprising >1350 specimens from the entire distribution range. Using species delimitation methods on mitochondrial DNA (mtDNA) sequences, we propose four primary species hypotheses for WCC. Sequences for several nuclear regions were screened but none showed significant variation within WCC. This result favours a single secondary species hypothesis and indicates the existence of a mito-nuclear discordance in WCC. Therefore, mtDNA groups were considered only as genetic units that carry information about ancient divergences within WCC and not as taxonomic units. The reconstruction of ancestral ranges and divergence time estimates were used to link the current genetic structure with paleogeographic processes. These results showed that the emergence of mtDNA groups in WCC could be related to the Messinian Salinity Crisis, the climate cooling during the Pliocene and Pleistocene, and (paleo)shifting of the Adriatic Sea coastline in the Padanovenezian Plain. The most recent common ancestor of the mtDNA groups most likely originated from Dalmatia (eastern Adriatic coast) as indicated by the reconstruction of ancestral ranges. This ecoregion, along with the Gulf of Venice Drainages, harbours a high genetic diversity and should be emphasised as an area of the highest conservation priority.