Toward Scientific Clarity in the Evolutionary Puzzle of Austropotamobius Crayfish

Abstract

Aim Illuminating the evolutionary history of Austropotamobius crayfish by uncovering patterns of biodiversity and biogeographical processes, thereby providing a foundation for accurate taxonomy and targeted conservation strategies. Location Europe. Time Period Miocene to present. Major Taxa Studied The crayfish genus Austropotamobius . Methods We synthesised existing knowledge and conducted additional analyses to resolve uncertainties in lineage divergence and distribution. Genetic variation across geographical regions was assessed using mitochondrial COI haplotypes, paired with accurate geolocation data from literature. Divergence times were estimated using a genus‐specific molecular clock calibrated to the tectonic‐driven separation of Austropotamobius bihariensis from its Dinaric relatives, based on 936 base pairs of concatenated COI and 16S mitochondrial sequences. To reconstruct historical connectivity and gene flow direction among regional populations, we applied coalescent‐based models comparing alternative scenarios. Results Our analysis suggests the common ancestor of Austropotamobius diverged ~30 Ma, coinciding with the temporary fragmentation of Balkanatolia from Western Europe, forming two major evolutionary lineages. In the west, between the Alps and Pyrenees, A. pallipes showed low genetic diversity and broad distribution. From this lineage, A. fulcisianus emerged around 14 Ma during an Alpine embayment, colonising the forming Italian Peninsula and later expanding into the southern Dinarides during the Messinian Salinity Crisis. Human‐mediated translocations further extended its range into Western and Northern Europe. The second major lineage, A. torrentium , spans Central and Eastern Europe and includes eight ancient, monophyletic and endemic lineages concentrated in the north‐central Dinarides (NCD), except for the most basal branch, A. bihariensis , located in the Apuseni Mountains. Two younger lineages expanded across the Balkans and Central Europe, likely beginning around 6.8 Ma with the formation of the Palaeo‐Danube system. Main Conclusions This study refines the evolutionary trajectory of Austropotamobius , highlights taxonomic clarification and underscores the need to reassess several lineages to support genuine, evolutionarily informed conservation strategies.

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