Molecular identification of endangered marine predators by barcoding ancient museum rostra of Mediterranean sawfish populations (Chondrichthyes, Pristidae)

Background: A growing concern in conserving threatened animals affected by human impact has been significant worldwide. Among marine animals, sawfishes (Chondrichthyes, Pristidae) are considered one of the most endangered families among lasmobranchs, resulting in extinction in many coastal areas around the world, including the Mediterranean Sea. Here, sawfish ccurred with two species, Pristis pristis and P. pectinata, until the second half of the last century and are now considered Critically ndangered/Possibly Extinct. The historical occurrence of sawfish in the area is documented by bibliographic/ archival records and y numerous preserved historical rostra available in museum collections. In this study we attempted to genetically characterize the istorical remains of sawfish from several European museums and to enable the investigation of their evolutionary and ecological relationships with global samples. Results: A total of 80 rostra specimens, dated from 1700 to 1900 and catalogued as unknown origin or Mediterranean (11), were collected from 11 European museums and were properly prepared for ancient DNA genetic analysis. Taxonomic identification at the species level was obtained through PCR amplification of small fragments (150 bp) of two mitochondrial markers commonly used for species identification (i.e., the mitochondrial COII and the NADH 2). Sequence comparison with currently available ones from public repositories and phylogenetic tree analyses indicated that the historical specimens belonged to four species, P. pristis, P. zijsron, P. pectinata, and Anoxypristis cuspidate, with a high frequency of mismatches (69%) between molecular identification and species museum cataloguing, when present. These preliminary data also showed the presence of two sequence sub-clusters in the poorly barcoded species P. zijsron. Significance: With the expansion of this initial analysis, we will contribute to increase the limited olecular data of these critically endangered large predators and to exploit historical genetic data for reconstructing phylogenetic/phylogeographic extent of the possibly extinct population of Mediterranean sawfish.