The Western Carpathians are a particularly interesting part of the Carpathian Arc. According to recent molecular data upon aquatic and terrestrial taxa, this mountain area is an important biodiversity hotspot of Europe. Moreover, the W Carpathians include rich systems of karst springs inhabited by specific fauna, where molecular diversity and phylogeographic patterns are yet to be fully explored. Our study aims to compare population genetic structure and molecular diversity of two related and commonly co-occurring riffle beetles, Elmis aenea (PWJ Müller, 1806) and Limnius perrisi (Dufour, 1843) in the springs and streams of the W Carpathians using the mitochondrial DNA barcoding fragment of the cytochrome c oxidase subunit I gene (COI). The relatively stable thermal and chemical conditions of springs throughout unfavourable climatic settings make these highly specific lotic systems potentially ideal for a long-term survival of some aquatic biota. Populations of both elmid species were relatively homogeneous genetically, with a single dominant haplotype. However, we revealed that E. aenea significantly dominated in the springs, while L. perrisi preferred streams. Relative isolation of the springs and their stable conditions were reflected in significantly higher molecular diversity of the E. aenea population in comparison to L. perrisi. The results of Bayesian Skyline Plot analysis also indicated the exceptional position of springs regarding maintaining the population size of E. aenea. On the other hand, it seems that streams in the W Carpathians provide more effective dispersal channels for L. perrisi, whose population expanded much earlier compared to E. aenea. Present study points out that different demographic histories of these two closely related elmid species are manifested by their different habitat preference and molecular diversity.

European mountains are important areas regarding biodiversity of the continent, and they also harbour diverse freshwater fauna, which is critically endangered in terms of the current species extinction. However, sufficient knowledge of this valuable part of European biota is no longer possible without molecular data. This study focuses on the genetic diversity and distribution patterns of the classical representative of the mountain freshwater fauna, caddisfly Rhyacophila tristis, in the Western Carpathians. Based on the COI mitochondrial marker, two genetic lineages (separate BINs) were identified. BIN_W was found in 16 localities in the western part of the study area, BIN_E in 44 eastern localities. The data obtained indicate that BIN_W occurs in a significantly narrower altitude range, BIN_E is more closely related to the Balkan populations than to co-occurring BIN_W, and that the contact zone of the lineages passes through the Western Carpathians. The study revealed phylogeographic and demographic differences between lineages, supporting hypothesis of their evolutionary independence and specific ecological preferences. The obtained genetic data shifted our knowledge on the populations of the studied caddisfly and suggested patterns that could be common to other freshwater species. This could help us to protect unique freshwater ecosystems and preserve European biodiversity.

We describe here a new species in the genus Disersus Sharp, 1882 from the Otongachi Reserve in Ecuador. Disersus otongachi sp.nov. is externally similar to other representatives of the genus, however, this species can be clearly distinguished for significantly longer antennae and the unique shape of the male genitalia.