The Odonata are considered among the most endangered freshwater faunal taxa. Their DNA‐based monitoring relies on validated reference data sets that are often lacking or do not cover important biogeographical centres of diversification. This study presents the results of a DNA barcoding campaign on Odonata, based on the standard 658‐bp 5′ end region of the mitochondrial COI gene, involving the collection of 812 specimens (409 of which barcoded) from peninsular Italy and its main islands (328 localities), belonging to all the 88 species (31 Zygoptera and 57 Anisoptera) known from the country. Additional BOLD and GenBank data from Holarctic samples expanded the data set to 1,294 DNA barcodes. A multi‐approach species delimitation analysis involving two distance (OT and ABGD) and four tree‐based (PTP, MPTP, GMYC and bGMYC) methods was used to explore these data. Of the 88 investigated morphospecies, 75 (85%) unequivocally corresponded to distinct molecular operational units, whereas the remaining ones were classified as ‘warnings’ (i.e. showing a mismatch between morphospecies assignment and DNA‐based species delimitation). These results are in contrast with other DNA barcoding studies on Odonata showing up to 95% of identification success. The species causing warnings were grouped into three categories depending on if they showed low, high or mixed genetic divergence patterns. The analysis of haplotype networks revealed unexpected intraspecific complexity at the Italian, Palearctic and Holarctic scale, possibly indicating the occurrence of cryptic species. Overall, this study provides new insights into the taxonomy of odonates and a valuable basis for future DNA and eDNA‐based monitoring studies.

中文翻译：

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潘多拉盒子中的意大利齿：一个全面的 DNA 条形码清单显示了全北尺度的分类警告。

蜻蜓目被认为是最濒危的淡水动物类群之一。他们基于 DNA 的监测依赖于经过验证的参考数据集，这些数据集通常缺乏或不涵盖重要的生物地理多样化中心。本研究展示了基于线粒体 COI 基因的标准 658-bp 5' 末端区域的 Odonata 的 DNA 条形码活动的结果，涉及收集来自意大利半岛及其主要岛屿的 812 个样本（其中 409 个样本有条形码）。 328 个地方），属于该国已知的所有 88 种（31 种接合翅目和 57 种异翅目）。来自 Holarctic 样本的其他 BOLD 和 GenBank 数据将数据集扩展到 1,294 个 DNA 条形码。一种多方法物种定界分析，涉及两个距离（OT 和 ABGD）和四个基于树的（PTP、MPTP、GMYC 和 bGMYC）方法用于探索这些数据。在 88 个研究的形态种中，75 个 (85%) 明确对应于不同的分子操作单元，而其余的则被归类为“警告”（即显示形态种分配和基于 DNA 的物种定界之间不匹配）。这些结果与其他对 Odonata 的 DNA 条形码研究形成对比，显示高达 95% 的识别成功。引起警告的物种根据它们是否显示低、高或混合遗传差异模式分为三类。单倍型网络的分析揭示了意大利、古北和全北范围内出乎意料的种内复杂性，这可能表明隐匿物种的出现。全面的，