The dark side of pseudoscorpion diversity: The German Barcode of Life campaign reveals high levels of undocumented diversity in European false scorpions

Abstract

DNA barcoding is particularly useful for identification and species delimitation in taxa with conserved morphology. Pseudoscorpions are arachnids with high prevalence of morphological crypsis. Here, we present the first comprehensive DNA barcode library for Central European Pseudoscorpiones, covering 70% of the German pseudoscorpion fauna (35 out of 50 species). For 21 species, we provide the first publicly available COI barcodes, including the rare Anthrenochernes stellae Lohmander, a species protected by the FFH Habitats Directive. The pattern of intraspecific COI variation and interspecific COI variation (i.e., presence of a barcode gap) generally allows application of the DNA barcoding approach, but revision of current taxonomic designations is indicated in several taxa. Sequences of 36 morphospecies were assigned to 74 BINs (barcode index numbers). This unusually high number of intraspecific BINs can be explained by the presence of overlooked cryptic species and by the accelerated substitution rate in the mitochondrial genome of pseudoscorpions, as known from previous studies. Therefore, BINs may not be an appropriate proxy for species numbers in pseudoscorpions, while partitions built with the ASAP algorithm (Assemble Species by Automatic Partitioning) correspond well with putative species. ASAP delineated 51 taxonomic units from our data, an increase of 42% compared with the present taxonomy. The Neobisium carcionoides complex, currently considered a polymorphic species, represents an outstanding example of cryptic diversity: 154 sequences from our dataset were allocated to 23 BINs and 12 ASAP units.

Life barcoded by DNA barcodes

“…In contrast, large intraspecific distance ranging from 0% to as much as 17.3% was noticed for COI genes in pseudoscorpions, which distorts the pattern of intra- and interspecific variation and spoils the existence of a barcode gap. This observation may result from undocumented species diversity, but also from anomalies in the COI evolution of these arachnids, indicating variable molecular change between species within different taxa (Muster et al 2021 ).…”

New data on pseudoscorpions (Arachnida: Pseudoscorpiones) in north-east Slovakia

“…Further studies are required to determine whether E. boldorii is more widespread in Central Europe than assumed by Muster et al (2004), or whether another cryptic species could be involved (cf. Muster et al 2021). Also, other aspects of the distribution need to be reconsidered.…”

“…and was found in eastern Slovakia in the Slovak Karst( Jászayová & Christophoryová 2019, Jászayová & Jászay 2021. Based on a recent molecular analysis(Muster et al 2021), this species was shown to exhibit high levels of cryptic diversity, which suggests that may consist of several, as yet undescribed, species. Future research with molecular methods appears to be necessary.…”

Molecular analyses of pseudoscorpions in a subterranean biodiversity hotspot reveal cryptic diversity and microendemism

“…Phylogenetic analyses were performed using a maximum likelihood (ML) 40 approach in IQ-TREE ver. 2.0.3 41 with 5000 ultrafast bootstraps 42 for: (i) the Dinaric dataset and additional sequences from central Europe 43 to check species-level determination (Supplementary File 1 online), and ii) Dinaric COI haplotypes only to select taxonomically relevant sequences for detailed analyses (Fig. 3 ).…”

“…Additionally, we examined relationships among populations of Neobisium sylvaticum (C.L. Koch, 1835) from Croatia and Germany, using published sequences 43 (Supplementary Fig. 2 online).…”