Summary. The 3 most common morphospecies of Uronychia, i.e. U. setigera, U. transfuga and U. binucleata, were examined in vivo and following protargol impregnation. Among these, U. transfuga is morphologically different to the others (large cell size, more macronuclear segments etc.). By contrast, U. setigera and U. binucleata are very similar and difficult to separate based only on their morphologies. Random amplified polymorphic DNA (RAPD) fingerprinting and amplified ribosomal DNA restriction analyses (ARDRA riboprinting) were therefore performed in order to confirm the division between them and to aid species identification. Using 4 different random primers the RAPD fingerprinting revealed 3 distinct patterns. Thus, 7 strains could be separated into 3 species with a similarity index of over 82% between different strains of the same species and only 30% to 40% between strains of different species. The unique restriction pattern of highly-conserved rDNA fragments (ARDRA) of different strains of U. setigera and U. binucleata using the enzyme Msp I was found to be species-specific and could be applicable for both species identification and species separation. According to our molecular analyses, the Uronychia-populations comprised at least 3 taxa (morphospecies). Moreover, the morphologically similar U. setigera and U. binucleata could be reliably separated and identified at the molecular level
