Detection of the Endangered Stone Crayfish Austropotamobius torrentium (Schrank, 1803) and Its Congeneric A. pallipes in Its Last Italian Biotope by eDNA Analysis

The stone crayfish, Austropotamobius torrentium, is a European freshwater crayfish. Although this species relatively widespread throughout the continent, it undergoing significant declines its range. However, as decline rates have not been quantified in detail, classified data deficient by IUCN Red List of Threatened Species. present study describes development and validation two species-specific assays based on hydrolysis probe chemistry for detection A. torrentium pallipes environmental DNA (eDNA) water samples collected Julian Alps Italy (Friuli Venezia Giulia). eDNA-based method was applied to 14 sites within Danubian Slizza basin, known be inhabited but with insufficient information their distribution. In addition, one station Tagliamento River basin sampled test performance probe. presence confirmed at 6 out 15 sites. At four these sites, detected first time. contrast, already harbour species. Finally, belonging basin. methodology described, which allows distinction between species, paves way parallel crayfish white-clawed (A. pallipes) through eDNA analysis.