Dispersal Capabilities Do Not Parallel Ecology and Cryptic Speciation in European Cheliferidae Pseudoscorpions (Pseudoscorpiones: Cheliferidae)

Abstract

The ability to disperse has continually shaped both the distribution and diversification of biota, and it affects the survival of the species with respect to wide-ranging habitat loss. As a response, organisms unable to spread by their own means often developed surrogate dispersal strategies. Pseudoscorpions possess small body sizes and cannot actively disperse over large distances and geographic barriers; therefore, they have adopted other ecological strategies. They are either sedentary and remain confined to stable environments or passively disperse via phoresy and are capable of inhabiting a wide variety of habitats, including temporary ones. In this paper, we use barcoding data to investigate the genetic diversity of four widely distributed and relatively morphologically uniform Cheliferidae genera Chelifer, Dactylochelifer, Rhacochelifer and Hysterochelifer. We aim to (i) test whether the genera harbor cryptic diversity and (ii) evaluate whether the genetic structure of the species parallels their dispersal capabilities and habitat preferences (i.e., ecological strategies). In general, we uncovered independent lineages within all analyzed genera, which indicates their need for a thorough and integrative taxonomic revision. More specifically, we detected a varying degree of genetic structuring among the lineages. Known phoretic species, as well as some species and delimited lineages that are not known to use this manner of dispersal, showed a complete lack of geographical structure and shared haplotypes over large distances, while other taxa had restricted distributions. We argue that genetic structure can be used as a proxy to evaluate species’ dispersal manner and efficacy. Our results also suggest that taxa inhabiting stable environments might use phoresy for their dispersal.

And Yet They Differ: Reconsiderations of Diversity within Dactylochelifer latreillii (Arachnida: Pseudoscorpiones)

“…We reanalyzed and extended the dataset from Just et al [25] with respect to the "Dactylochelifer latreillii morphotype". Field surveys along the German coast and in the northeast German plain were carried out in 2022-2023 for material enrichment and to reveal local distribution and habitat affinities.…”

“…The procedure followed, with minor variations, the methodology used in Just et al [25] to obtain the most comparable results. Whole genomic DNA was extracted from whole specimens using the Genomic DNA Extraction Kit (Tissue) (Geneaid, Taiwan) following the manufacturer's protocol.…”

“…Alignment length was set to 555 bp. The obtained alignment ("Dactyloche-lifer_total") contained 170 sequences (including outgroups) (Alignment S1), 81 ingroup sequences were taken from Just et al [25] (including one from [49]), and 88 were newly generated. Finally, we obtained a reduced matrix ("Dactylochelifer_haplo") of unique haplotypes (60 sequences, including outgroups) using TCS [50].…”

“…On the other hand, in taxa that disperse phoretically (i.e., transport attached to host species) over long distances (Chernetidae, Cheliferidae) [22], initial studies have suggested little genetic structure and better correspondence with traditional taxonomy [23,24]. Recent studies with geographically more inclusive sampling, however, revealed examples of cryptic diversity in these families as well [25].…”

“…The present study was inspired by the coincidence of two occurrences: first, the detection of three deeply diverged COI (cytochrome c oxidase subunit I) lineages within the Dactylochelifer latreillii morphotype [25], and second, a field survey on behalf of the German Red List Centre in order to clarify the status of D. latreillii septentrionalis in Germany. Through dense sampling in northern Germany, the distribution pattern could be refined and new insights in habitat preferences were obtained.…”