First record of the cyanobacterial genus Wilmottia (Coleofasciculaceae, Oscillatoriales) from the South Orkney Islands (Antarctica)

Two cyanobacterial morphotypes isolated from Signy Island, South Orkney Islands, maritime Antarctica were characterised using a polyphasic approach combining morphological, cytological and molecular analyses. These analyses showed that the strains grouped with members of the genus Wilmottia. This genus has three species, W. murrayi, W.stricta, and W. koreana. Both morphotypes analysed in this study were placed within the clade of W. murrayi. This clade showed a well-supported separation from Antarctica and New Zealand strains, as well as the strains from other regions. W. murrayi was first described from Antarctica and is now known from several Antarctic regions. Confirmation of the occurrence of W. murrayi at Signy Island significantly extends its known distribution in Antarctica. In addition, a new combination, W. arthurensis, is suggested for Phormidium arthurensis.