The genus Potamometra Bianchi, 1896 represents big rheophilic semi‐aquatic bugs that typically inhabit middle‐altitude mountainous streams. Here, we integrated molecular and morphological data for delimiting species boundaries and understanding the evolutionary history of the genus Potamometra. Twenty‐seven complete mitochondrial genomes of Potamometra were sequenced, with samples representing most of the known geographically distributed locations around the Sichuan Basin. The results of different species delimitation methods (ABGD, bPTP, GMYC and BPP) based on the monolocus or multilocus data strongly supported the existence of two cryptic new species (Potamometra anderseni Zheng, Ye & Bu, sp. nov. and Potamometra zhengi Zheng, Ye & Bu, sp. nov.) although more entities were found in the tree‐based delimitation methods. The two new species were successfully validated using morphological characters within a detailed taxonomic framework. Phylogenetic analyses supported the reciprocal monophyly of the seven highly node‐supported clades, which were matched with the five known species and two new taxa. A novel gene arrangement pattern that two trnF (trnF1 and trnF2) genes separated by an intergenic spacer (IGS) were found in all the species except the sister group of Potamometra berezowskii Bianchi, 1896 and Potamometra linnavuorii Chen, Nieser & Bu, 2016. This gene rearrangement event could be explained by the tandem duplication and random loss (TDRL) model. Our study emphasized that the combination of molecular sequence data, morphological characters and mitochondrial structural information could improve the accuracy of species delimitation.

中文翻译：

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综合分类法揭示了嗜流性属 Potamometra（半翅目：Gerridae）中隐藏的物种多样性

Potamometra Bianchi 属，1896 年代表大型流变型半水生昆虫，通常栖息在中海拔山区溪流中。在这里，我们整合了分子和形态学数据，以划定物种边界并了解 Potamometra 属的进化历史。对 Potamometra 的 27 个完整线粒体基因组进行了测序，样本代表了四川盆地周围大多数已知的地理分布位置。基于单位点或多位点数据的不同物种定界方法（ABGD、bPTP、GMYC 和 BPP）的结果有力地支持了两个隐秘新物种（Potamometra anderseni Zheng, Ye & Bu, sp. nov. 和 Potamometra zhengi Zheng， Ye & Bu, sp. nov.) 虽然在基于树的定界方法中发现了更多实体。使用详细分类框架内的形态特征成功验证了这两个新物种。系统发育分析支持七个高度节点支持的进化枝的相互单系性，它们与五个已知物种和两个新分类群相匹配。除了 Potamometra berezowskii Bianchi, 1896 和 Potamometra linnavuorii Chen, Nieser & Bu, 2016 的姐妹群外，在所有物种中都发现了一种新的基因排列模式，即由基因间间隔区 (IGS) 分隔的两个 trnF（trnF1 和 trnF2）基因。基因重排事件可以通过串联重复和随机丢失（TDRL）模型来解释。我们的研究强调结合分子序列数据、形态特征和线粒体结构信息可以提高物种定界的准确性。