Detailed integrative taxonomic analysis reveals large-scale species misidentification of barnacles based on DNA barcoding data

Abstract

Abstract Morphological species identification is the traditional way to identify species. More recently, biodiversity studies have depended on DNA barcoding for species identification. Mismatches between morphological and genetic species identification caused by voucher specimen misidentifications lead to ambiguous species identification. We used barnacles of the genera Amphibalanus and Balanus to investigate this issue. The purpose of this study was to assess the accuracy of the Barcoding of Life database and determine the true species affinity of three inconsistent barnacle barcode index numbers using an integrative taxonomic approach. To this end, we re-identified barcoded voucher specimens, or we identified specimens based on a dichotomous key that we barcoded subsequently. We found that 75% of Barcoding of Life clades representing genetic species showed inconsistent species assignments. One clade (BOLD: AAG0069), containing mostly unidentified Balanus sp. individuals, was morphologically and genetically Balanus balanus (Linneaus, 1758); a second clade (BOLD: AAB1410), containing specimens mostly identified as B. balanus, turned out to be morphologically and genetically Balanus crenatus Bruguière, 1789; and a third clade (BOLD: AAE2482), containing different species of Amphibalanus, was Amphibalanus improvisus (Darwin, 1854). This study showed that morphological species identification and taxonomic expertise can resolve the widespread misidentification in barcoding data. To prevent this problem in the future, morphological taxonomy and molecular species identification need to interact more closely.