New records for Freshwater Benthic Diatom Flora of Iran, from Damavand River basin (Central Alborz), Iran

Diatoms are a key group of organisms of the periphyton and have a significant contribution to primary production in rivers. Despite their importance, little information exists about the taxonomy and distribution of periphytic diatoms in Iran. Central Alborz is one of the hotspots known globally for its fauna and flora and the Damavand River is one of the permanent rivers flowing in the region. Epilithic diatom samples were taken along the Damavand River basin between the summer of 2017 and the spring of 2019 to determine the benthic diatom flora. As a result, five species within the genera Gomphonema, Cymbella, Cymbopleura, and Sellaphora were found as new records from the Central Alborz. These species include Cymbella affinis var. angusta (Krammer) W. Silva, Cymbopleura similiformis Krammer, Gomphonema innocens Reichardt, Sellaphora capitata D.G. Mann & S.M. McDonald and Sellaphora lanceolata D.G. Mann & S.J.M. Droop.  The morphology of these taxa, comparisons to similar taxa, and geographic distributions are discussed. These results expand the knowledge of diatom diversity in the Central Alborz Region.