Abstract
The Carpathians are one of the key biodiversity hotspots in Europe. The mountain chain uplifted during Alpine orogenesis and is characterised by a complex geological history. Its current biodiversity was highly influenced by Pleistocene glaciations. The goal of the current study was to examine the phylogenetic and demographic history of Gammarus balcanicus species complex in the Carpathians using multiple markers as well as to delimit, using an integrative approach, and describe new species hidden so far under the name G. balcanicus. Results showed that divergence of the studied lineages reaches back to the Miocene, which supports the hypothesis of their survival in multiple micro refugia. Moreover, the increase of their diversification rate in the Pleistocene suggests that glaciation was the driving force of their speciation. The climatic changes during and after the Pleistocene also played a major role in the demography of the local Carpathian lineages. Comparison of diversity patterns and phylogenetic relationships of both, the mitochondrial and nuclear markers, provide evidence of putative hybridisation and retention of ancient polymorphism (i.e., incomplete lineage sorting). The morphological examination supported the existence of two morphological types; one we describe as a G. stasiuki sp. nov. and another we redescribe as a G. tatrensis (S. Karaman, 1931).
Highlights
The Carpathians are one of the key biodiversity hotspots in Europe
The Automatic Barcode Gap Discovery (ABGD) and ASAP provided similar results, among 10 resulting partitions P was stable for 0.0269–0.0437, with ASAP species threshold for preferred partition being: 0.0447 p-distance, the data was divided into 18 molecular operational taxonomical units (MOTU) (G1–G18)
Multilocus species delimitation (STACEY) suggested the presence of 36 MOTUs identical to Barcode Index Number (BIN) used as minimal clusters, from which 21 fell into G. tatrensis and 3 to G. stasiuki sp. nov
Summary
The Carpathians are one of the key biodiversity hotspots in Europe. The mountain chain uplifted during Alpine orogenesis and is characterised by a complex geological history. Recent phylogeographic studies on several geographically widespread Gammarus morphospecies pointed out to outstanding cryptic and pseudo-cryptic diversity with an ancient divergence between phylogenetic lineages (e.g.,14,15,20–25) Unrevealing such a high level of hidden diversity stimulated further taxonomic studies, resulting in the description of new taxa, based either on a modern integrative approach using morphological, ultrastructural and molecular characters or, in the case of species for which the morphological distinction was impossible, based on molecular descriptive characters only (e.g.,14,15). Recently growing evidence that much of the area remained unglaciated during the Last Glacial Maximum (LGM), corroborated by results of palaeoecological and molecular phylogeographic studies, has largely altered such view (for an overview s ee[30,31]) It is generally accepted, that the Carpathians acted as refugium for temperate biota during the LGM but, during warmer episodes, for the coldadapted taxa, either at higher elevations (e.g.,32,33) or in habitats such as fens and peat bogs at lower elevations[34]. High lineage diversification in the Carpathian springs and streams, indicating long local divergence processes, even in the northernmost parts of the Carpathian Arc (i.e., the Western Carpathians), has been shown for the two gammarid morphospecies complexes widespread in Europe, i.e., Gammarus balcanicus 20,24 and G. fossarum[16,39]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
