Hidden in our pockets: building of a DNA barcode library unveils the first record of Myotis alcathoe for Portugal.

We added four new Barcoding Index Numbers (BINs) to existing Chiroptera barcodes on BOLD, two belonging to Myotis escalerai, one to Plecotus auritus and the other to Rhinolophus hipposideros. Surprisingly, one of the samples initially identified in the field as Myotis mystacinus turned out to be Myotis alcathoe, which represents the first record of this species for Portugal. The presence of Nyctalus noctula in Portugal was also genetically confirmed for the first time. This case study shows the power and value of DNA barcoding initiatives to unravel new data that may be hidden on biological collections.