Cymbella golestanica sp. nov. a new diatom species from Agh Su Waterfall, Golestan National Park, Northeastern Iran

Abstract

A new species of Cymbella is characterized by morphological, ultrastructural and ecological remarks. The species was found in diatom samples collected from Agh Su waterfall located in western part of Golestan National Park. Cymbella golestanica sp. nov is assigned to the C. leptoceros group based on the areola density, the absence of stigmata and lanceolate shape. The most similar taxa are C. diminuta and C. hustedtii, however in our taxon stria is less dense than the C. diminuta types and more loosely distributed, and apices are completely protracted with ventrally broadened valves and axial area. The most diagnosing features with C. hustedtii are also valve apices and length/width ratio. C. golestanica was also compared with C. subleptoceros and C. designata. Ecologically the newly described species was found as epilithic in alkaline water with low conductivity.