Three new records for diatoms from the Nišava River and its tributary, the Jerma River (Southern Serbia)

The main objective of this paper is to report three benthic diatom species from the Nišava and Jerma Rivers, which prove to be new findings in the context of the Serbian diatom flora. These are also new distributional records for all three species. Monthly samples (from stones, sediments and macrophytes) were collected from May 2008 to May 2009. Diatom frustules were cleaned using chemical agents, and mounted on permanent slides. Descriptions (main valve measurement of the populations in the Nišava and Jerma Rivers), ecology, distribution in Serbia and Europe, and appropriate photomicrographs of three species are presented. Navicula novaesiberica Lange-Bertalot and Neidiomorpha binodiformis (Krammer) Lange-Bertalot & Cantonati are rarely found in Europe, while Parlibellus protracta (Grunow) Witkowski is more common. Navicula novaesiberica and Neidiomorpha binodiformis were found at higher water temperatures in comparison to temperatures reported in the existing literature. These new taxa significantly contribute to diatom floristic richness of the Nišava and Jerma Rivers in Serbia.