Description of Azorothrix ramosa gen. et sp. nov. (Tolypotrichaceae, Cyanobacteria), a new Tolypotrichaceae from Atlantic oceanic islands

The Tolypotrichaceae is a well-defined family within the filamentous heterocyst-forming cyanobacteria. However, the morphological and genetic similarity of some of its genera is very high, making the taxonomic assessment and the description of new taxa in this family challenging. Here we describe six strains of Tolypothrix-like cyanobacteria that were isolated from freshwater lakes and streams from Sao Miguel Island (Azores Archipelago, Portugal), and deposited in the BACA collection. All strains showed morphological similarities, restricting them to the same taxa, with the phylogenetic analysis revealing a distinct position in the Tolypotrichaceae clade. A deeper analysis of the morphological, ecological, and genetic (16S rRNA and 16S -23S rRNA internal transcribed spacer) data, and comparison with known genera in the Tolypotrichaceae, allowed the description of the taxon as Azorothrix ramosa gen. et sp. nov. in the Tolypotrichaceae family.