| Abstract: | A taxonomic reevaluation of the paralytic shellfish toxin (saxitoxins) producing cyanobacterium Aphanizomenon flos‐aquae Ralfs ex Born. & Flah. LMECYA31 was done using morphology and 16S rRNA gene sequences. We found that strain LMECYA31 was incorrectly identified as Aph. flos‐aquae based on (a) lack of bundle formation in trichomes, (b) shape of terminal cells in the trichomes, (c) lower similarity (<97.5%) in the 16S rRNA gene sequences relative to those of Aph. flos‐aquae, and (d) comparison within a phylogenetic tree of 16S rRNA gene sequences. The shape of the terminal trichome cells and the shape and size of the vegetative cell, heterocyst, and akinete in strain LMECYA31 match characters of Aph. issatschenkoi (Ussachew) Proschkina‐Larvernko. 16S rRNA gene sequences and phylogenetic clusters constructed from 16S rRNA gene sequences support our conclusion that strain LMECYA31 should be Aph. issatschenkoi. |
