Erratum: Corrigendum: Salvi D, Al-Kandari M, Oliver PG, Berrilli E, Garzia M (2022) Cryptic marine diversity in the northern Arabian Gulf: an integrative approach uncovers a new species of oyster (Bivalvia: Ostreidae), Ostreaoleomargarita. Journal of Zoological Systematics and Evolutionary Research 2022: 7058975. https://doi.org/10.1155/2022/7058975.

[This corrects the article DOI: 10.1155/2022/7058975.].

Sharpening the DNA barcoding tool through a posteriori taxonomic validation: The case of Longitarsus flea beetles (Coleoptera: Chrysomelidae).

The accuracy of the DNA barcoding tool depends on the existence of a comprehensive archived library of sequences reliably determined at species level by expert taxonomists. However, misidentifications are not infrequent, especially following large-scale DNA barcoding campaigns on diverse and taxonomically complex groups. In this study we used the species-rich flea beetle genus Longitarsus, that requires a high level of expertise for morphological species identification, as a case study to assess the accuracy of the DNA barcoding tool following several optimization procedures. We built a cox1 reference database of 1502 sequences representing 78 Longitarsus species, among which 117 sequences (32 species) were newly generated using a non-invasive DNA extraction method that allows keeping reference voucher specimens. Within this dataset we identified 69 taxonomic inconsistencies using barcoding gap analysis and tree topology methods. Threshold optimisation and a posteriori taxonomic revision based on newly generated reference sequences and metadata allowed resolving 44 sequences with ambiguous and incorrect identification and provided a significant improvement of the DNA barcoding accuracy and identification efficacy. Unresolved taxonomic uncertainties, due to overlapping intra- and inter-specific levels of divergences, mainly regards the Longitarsus pratensis species complex and polyphyletic groups L. melanocephalus, L. nigrofasciatus and L. erro. Such type of errors indicates either poorly established taxonomy or any biological processes that make mtDNA groups poorly predictive of species boundaries (e.g. recent speciation or interspecific hybridisation), thus providing directions for further integrative taxonomic and evolutionary studies. Overall, this study underlines the importance of reference vouchers and high-quality metadata associated to sequences in reference databases and corroborates, once again, the key role of taxonomists in any step of the DNA barcoding pipeline in order to generate and maintain a correct and functional reference library.

First molecular identification of the tapeworm Mesocestoides litteratus from an Italian wall lizard (Podarcis siculus).

The cyclophyllidean cestodes of the genus Mesocestoides are parasites infecting a variety of carnivorous vertebrates. The complete life cycle of these tapeworms is not clear yet, but some reptiles, amphibians, birds and micro-mammals have been indicated as intermediate hosts. Although Mesocestoides spp. are considered endemic in Europe, infections by the metacestode form, the tetrathyridium, are reported less commonly than are infections by adult worms. In the present study, a peritoneal infection by Mesocestoides tetrathyridia in a wall lizard (Podarcis siculus) collected in central Italy is described. The phylogenetic position of the metacestodes was assessed using the barcode region COI and species delimitation methods, i.e. Automatic Barcode Gap Discovery (ABGD) and Bayesian implementation of the Poisson Tree Processes model (bPTP). COI sequence analysis assigned the isolates from the wall lizard to Mesocestoides litteratus, as confirmed by species delimitation and phylogenetic analyses. M. litteratus has been observed in Europe mainly in the definitive hosts (dogs, cats and foxes), and never identified in the Mediterranean region. This study represents the first evidence of parasitic infection by tetrathyridia of M. litteratus in P. siculus in Italy.