Surprisingly high genetic divergence of the mitochondrial DNA barcode fragment (COI) within Central European woodlice species (Crustacea, Isopoda, Oniscidea)

Abstract

DNA barcoding has become the most popular approach for species identification in recent years. As part of the German Barcode of Life project, the first DNA barcode library for terrestrial and freshwater isopods from Germany is presented. The analyzed barcode library included 38 terrestrial (78% of the documented species of Germany) and five freshwater (63%) species. A total of 513 new barcodes was generated and 518 DNA barcodes were analyzed. This analysis revealed surprisingly high intraspecific genetic distances for numerous species, with a maximum of 29.4% for Platyarthrus hoffmannseggii Brandt, 1833. The number of BINs per species ranged from one (32 species, 68%) to a maximum of six for Trachelipus rathkii (Brandt, 1833). In spite of such high intraspecific variability, interspecific distances with values between 12.6% and 29.8% allowed a valid species assignment of all analyzed isopods. The observed high intraspecific distances presumably result from phylogeographic events, Wolbachia infections, atypical mitochondrial DNAs, heteroplasmy, or various combinations of these factors. Our study represents the first step in generating an extensive reference library of DNA barcodes for terrestrial and freshwater isopods for future molecular biodiversity assessment studies.

When standard DNA barcodes do not work for species identification: intermixed mitochondrial haplotypes in the Jaera albifrons complex (Crustacea: Isopoda)

“…com). Sequences for the chosen CO1 outgroup species, Jaera sarsi Valkanov, 1936(Raupach et al 2022, and other available J. albifrons sequences (Radulovici et al 2009;Raupach et al 2015) from outside of Norway (Table 1), were downloaded from BOLD and aligned with our own sequences using MUSCLE (Edgar 2004) in MEGA11 version 11.0.8 (Tamura et al 2021). All CO1 sequences were uploaded to BOLD and subjected to the Barcode Index Number (BIN) analysis which clusters sequences with a certain level of similarity (Ratnasingham and Hebert 2013).…”

Integrative Taxonomy Approach Reveals Cryptic Diversity within the Phoretic Pseudoscorpion Genus Lamprochernes (Pseudoscorpiones: Chernetidae)

“…The European biota has been extensively studied, and as a result, its diversity and evolutionary history are among the best understood world-wide. This is particularly true for western, central and northern parts of Europe [ 21 , 22 , 23 , 24 ]; however, ongoing barcoding efforts continue to elucidate the existence of overlooked arthropod diversity even in these well-studied regions [ 25 , 26 , 27 ]. Arachnids are no exception [ 28 , 29 ], due to a combination of their often challenging morphology-based species recognition and taxonomic neglect [ 30 ].…”

Detailed DNA barcoding of mayflies in a small European country proved how far we are from having comprehensive barcode reference libraries

“…However, for many non-insect taxa (e.g. crustaceans), the threshold distance can be much greater than 10% (Lagrue et al, 2014;Raupach et al, 2022) and has also been significantly exceeded in numerous insect taxa (Zhang & Bu, 2022), including mayflies (Leys et al, 2016;Morinière et al, 2017;Múrria et al, 2017). Exceeding this threshold indicated the presence of significant gaps in our knowledge, leading to the opening of Pandora's box full of unknown cryptic taxa (Blair et al, 2005;Hebert et al, 2004;Stireman et al, 2005), but in some cases, they may not be associated with reproductive isolation (Lagrue et al, 2014).…”