Variability of Ephemeroptera of family Baetidae (Insecta, Ephemeroptera, Baetidae)

This thesis deals with a variability of the Baetis fuscatus species-group (Ephemeroptera: Baetidae). This study contains three main topics: The first one is distinguishing between two highly similar species, Baetis scambus and Baetis fuscatus based on morfological structures, specifically their mouthparts - labial palps. To analyze the shape of the labial palps, I applied a computerized outline analysis. Second topic is focused on the validity of Baetis beskidensis as a distinct species based on the morphology and DNA sequences (obtained for the topotypical material for the first time). And finally, I also investigated some samples from Corsica in attempt to discover new species of the Baetis fuscatus species-group. I found that most probably it is not possible to distinguish between Baetis scambus and Baetis fuscatus based on the shape of their labial palps. Baetis beskidensis is morfologically different, but genetically not distinctly separated from other representatives of the Baetis fuscatus species-group. I didn´t discover any distinct morphological differences in specimens from Corsica, pointing to the possible existence of new species