Saline-alkaline lakes are extreme environments that
limit the establishment and development of life. The
Nhecol^andia, a subregion of the Pantanal wetland in
Brazil, is characterized by the existence of ~500
saline-alkaline lakes, which support an underexplored
and rich diversity of microorganisms. In this study,
unicellular and homocytous cyanobacteria from five
saline-alkaline lakes were accessed by culturedependent
approaches. Morphological evaluation
and analyses of near complete sequences (~1400 nt)
of the 16S rRNA genes were applied for
phylogenetic and taxonomic placement. This
polyphasic approach allowed for the determination
of the taxonomic position of the isolated strains
into the following genera: Cyanobacterium,
Geminocystis, Phormidium, Leptolyngbya, Limnothrix,
and Nodosilinea. In addition, fourteen
Pseudanabaenales and Oscillatoriales representatives
of putative novel taxa were found. These
sequences fell into five new clades that could
correspond to new generic units of the
Pseudanabaenaceae and Phormidiaceae families.
Key index words: alkaline environment; Brazil; Chroococcales;
extreme environment; Oscillatoriales; Phylogeny;
polyphasic approach; Pseudanabaenales; saline
environment; Synechococcales; tropical wetlands