Data from: DNA barcoding and mini-barcoding as a powerful tool for evolutionary ecology studies of feather mites

Feather mites (Astigmata: Analgoidea, Pterolichoidea) are among the most important and commonly occurring ectosymbionts living on birds. Basic questions on the evolutionary ecology of feather mites remain unknown because feather mite species identification is often only possible for adult males and it is laborious even for specialized taxonomists, thus precluding massive identifications. Here we tested DNA barcoding as a useful molecular tool to identify feather mites from passerine birds. 361 specimens of 72 species of feather mites from 68 species of European passerine birds from Russia and Spain were barcoded. The accuracy of barcoding and mini-barcoding was tested. Moreover, threshold choice (a controversial issue in barcoding studies) was also explored in a new way, by calculating through simulations the effect of sampling effort (in species number and species composition) on threshold calculations. We found one 200 bp mini-barcode region that showed the same accuracy than the full length barcode (602 bp) and it was surrounded by conserved regions potentially useful for group specific degenerated primers. Species identification accuracy was perfect (100%) but decreased when singletons or species of the Proctophyllodes pinnatus group were included. In fact, barcoding confirmed previous taxonomical issues within the Proctophyllodes pinnatus group. Following an integrative taxonomy approach, we compared our barcode study with previous taxonomic knowledge on feather mites, discovering three new tentative cryptic species and validating three previous morphologically different (but still undescribed) new species.