Integrative taxonomy uncovers hidden species diversity in the rheophilic genus Potamometra (Hemiptera: Gerridae)

Abstract

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.

First complete mitogenomes of Diamesinae, Orthocladiinae, Prodiamesinae, Tanypodinae (Diptera: Chironomidae) and their implication in phylogenetics

“…Genome annotation was conducted as previously described in Zheng et al (2020) . Specifically, the transfer RNA (tRNA) genes and their secondary structures were detected by MITOS2 webserver ( http://mitos2.bioinf.uni-leipzig.de/index.py ) ( Bernt et al, 2013 ) with invertebrate mitochondrial genetic code.…”

Integrative species delimitation based on COI, ITS, and morphological evidence illustrates a unique evolutionary history of the genus Paracercion (Odonata: Coenagrionidae)

“…Correctly identifying species boundaries is important in taxonomic studies. Species delimitation based on molecular data plays an important role in integrative taxonomy ( Satler, Carstens & Hedin, 2013 ; Andujar et al, 2014 ; Kergoat et al, 2015 ; Huang & Knowles, 2016 ; Noguerales, Cordero & Ortego, 2018 ; Vidigal et al, 2018 ; Zhang et al, 2018 ; Masonick & Weirauch, 2020 ; Zheng et al, 2020 ). A variety of species delimitation methods based on molecular data are used in taxonomic and systematic studies for testing species boundaries ( Sites & Marshall, 2003 ; Flot, 2015 ).…”

The first comprehensive DNA barcode reference library of Chinese Tanytarsus (Diptera: Chironomidae) for environmental DNA metabarcoding

“…Incomplete lineage sorting (Willyard et al., 2009), horizontal gene flow (Naciri et al., 2012), recent speciations and insufficient taxon sampling (Luo et al., 2015; Zhang et al., 2010), can lead to inaccurate species delimitation. Therefore, an integrative taxonomy with molecular, morphological and ecological data is crucial to explore species boundaries (Galimberti et al., 2012; Hebert et al., 2004; Schutze et al., 2017; Zheng et al., 2020). For instance, species boundaries of closely related species within two Tanytarsus species groups were explored based on both morphology and DNA, and eight cryptic species were uncovered and described (Lin et al., 2018a, 2018b).…”