A glacial relict in the Carpathian caves - population variability or a species complex?

Abstract

The collembolan Protaphorura janosik Weiner, 1990, is a widespread and abundant troglobiotic species with a distribution range limited to the Western and Eastern Carpathian Mountains, in Central Europe. Owing to limited dispersal ability, its populations are probably isolated to some extent in the subterranean environments of different geomorphological units. In five of nine populations examined for morphological variability, genetic analyses were also carried out. Analysis of 10 measurable or countable morphological traits by non-metric multidimensional scaling (NMS) showed a slight separation of neighbouring localities; however, no clear geographical pattern was evident among distant populations. In contrast, genetic analysis based on partial sequences of the mitochondrial COI gene showed a different pattern. Although only eight haplotypes out of 88 sequences were detected, their geographical distribution points towards a high population differentiation. One haplotype was shared by two populations from adjacent caves (the Nová Kresanica and Mylna caves), while all the others were unique to different populations. A Mantel test showed a significant correlation of the geographical and genetic distances. Genetic distances (K2P) between the populations ranged from 0.1% to 3.1%, suggesting the existence of geographical isolates. The bacterial genus Wolbachia was detected only in one population from a pseudokarst (sandstone) cave, while it was absent in the remaining populations occupying karst caves.

Adaptations to Subterranean Environments

“…To avoid contamination, all DNA laboratory work was performed under sterile conditions and using barrier tips. Total DNA was extracted using the Qiagen DNeasy Blood and Tissue Kit according to the manufacturer's modified protocol (see Parimuchová et al, 2017). A polymerase chain reaction (PCR) (Saiki et al, 1988) was performed with a reaction volume of 12.5 µl consisting of 1 µl template DNA (not quantified), 10 × PCR buffer (TopBio), 12.5 mM dNTP mix, 5 µM of each primer, and 0.125 units of Taq polymerase (TopBio) on a GenePro (Bioer Co., Ltd, China) thermal cycler.…”

“…Continentalization of Europe during the Neogene, triggered by the Alpidic orogeny and the simultaneous retreat of the Paratethys Sea, led to isolated evolution and an increase in the endemicity of the entire local biota (Neubauer et al, 2015). The central Western Carpathians formed an island in the Paratethys during the Burdigalian and Langhian stages of the Miocene, which ranged from 20.4 to 13.6 Mya (Kováč et al, 2017). This longterm isolation undoubtedly led to the independent evolution of the local biota after previous colonization of the territory by lineages from southern European orogenic units (e.g., Kováč, et al 2014;Haase et al, 2021).…”