부산대학교 도서관

Several taxa from the genus Cyclotellaobserved in two ancient sister lakes, Prespa and Ohrid were studied and compared to the regionally common species Cyclotella ocellata. Two new species are described from Lake Prespa and additionally Cyclotella thienemanniivar. minusculafrom Lake Ohrid is formally transferred to Cyclotella minuscula(Jurilj) Cvetkoska stat. nov. Cyclotella paraocellatasp. nov. is compared to C. ocellataand is characterized by a large morphological variability in the fossil and recent diatom assemblages. Cyclotella prespanensissp. nov. is described and distinguished as a separate taxon by its valve size range, colliculate central area, stria density and number and position of marginal fultoportulae and rimoportulae. The investigation reveals C. ocellataand C. minusculaas the only taxa of the genus Cyclotellapresent in fossil and contemporary diatom assemblages from both Lake Ohrid and Lake Prespa.