A new species of Brasilonema (Scytonemataceae, Cyanoprokaryota) from Tolantongo, Hidalgo, Central Mexico.

New approaches in taxonomy and the introduction of molecular tools have substantially changed the taxonomy of cyanobacteria, leading to new genera and species being defined based on genetic and morphological investigations. In addition, molecular tools have confirmed several previously defined cyanobacteria genera, including some based on morphological and ecological features. Several of them have also been split into new generic entities, such as Brasilonema. In the central region of Mexico, several populations have been identified to share some traits with this new genus. In the region of Tolantongo, Hidalgo (Hgo), we found cyanobacteria populations that correspond to Brasilonema description (Fiore et al. 2007), however the development of trichomes and hormogonia did not agree with the diagnosis of Brasilonema. We describe and analyze the cyanobacteria populations that we found in Tolantongo, and compare their features with the diagnostic generic features and those of several Brasilonema species. The results of morphological analyses were tested using molecular phylogenetic data derived from 16S RNA gene sequencing and the use of marker cpcBA-IGS for phycocyanin operon. From our analyses we conclude that the strain from Tolantongo belongs to the genus Brasilonema, and the differences observed are sufficient to propose a new species.