A new species of Austropotamobius Skorikov, 1907 (Decapoda: Astacidae: Astacidae) from the late Miocene (Messinian) of Slovenia, with remarks on the evolution of European crayfishes

Abstract Crayfishes are rather rare in the fossil record, limiting our understanding of their evolutionary history. We describe and discuss a fossil crayfish from the Miocene of Slovenia. This fossil, comprising only the cephalothorax, first pereiopod, and another cheliped, seems closely allied to AustropotamobiusSkorikov, 1907, but also bears an epistome and postorbital carina reminiscent of AstacusFabricius, 1775. For these reasons, it is tentatively assigned to Austropotamobius. It differs from all other Austropotamobius species by the shapes of its epistome cephalic lobe, and postorbital carina, and resemble Austropotamobius torrentium (von Paula Schrank, 1803) most due to its ornamentation. It is therefore described as a new species, Austropotamobius plenicarisp. nov. The new species is associated with brackish water ostracods, most likely reworked from slightly older sediments, suggesting a late Miocene (Messinian) age. The origin of this species and its age show it lived long after the split between Astacus and Austropotamobius, and also probably after the split between the two Austropotamobius species (Au. pallipes and Au. torrentium), and may have been contemporary to, and lived in the area of the diversification of Au. torrentium haplotypes.