Phylogenetic position and taxonomy of three heterocytous cyanobacteria dominating the littoral of deglaciated lakes, James Ross Island, Antarctica

Several communities of autotrophic microorganisms, in which cyanobacteria are dominant or play a substantial role in their structure, were studied on the deglaciated Ulu Peninsula, northern part of James Ross Island, NW Weddell Sea, Antarctica, in 2007-2009. Our results were compared with similar data from maritime Antarctica (King George Island, South Shetland Islands, 2005). Characteristics and taxonomic description of three important heterocytous species, which participate in cyanoprokaryotic assemblages in the littoral of small lakes, seepages, and on wetted rocks during the Antarctic summer season, are included in this study. They belong to the form-genera Calothrix and Hassallia, respectively, and are unidentifiable according to the present determination literature. Therefore, after a polyphasic evaluation, they are described as three new species, Calothrix elsteri sp. nova, Hassallia andreassenii sp. nova, and Hassallia antarctica sp. nova. 16S rRNA gene sequencing of isolated strains confirmed the taxonomic position of all three species, and their ecology and seasonal development are described. All three discovered species are dominant in distinct communities with a specialized ecology and may be endemic for coastal maritime Antarctica.