Phenotype diversity and phylogeny of selected Scytonema-species (Cyanoprokaryota) from SE Brazil

Members of the genus Scytonema belong to prominent components of microflora of tropical and subtropical soils, but their diversity and taxonomic classification is still little known. Molecular analyses of isolated strains, but also the morphological and ecological examination of natural populations are important for the starting revisions. Here we present phenotype characteristics of fourteen morphotypes of the cyanobacterial genus Scytonema from the SE Brazil, mostly from the state Sao Paulo and from the Atlantic Rainforest (ecosystem of Mata Atlantica). The populations of studied Scytonema species are ecologically significant, as they hold the dominant position in the microvegetation communities of lateritic and forest soils and of stony substrates (less frequently also aquatic forms). Species commonly distributed throughout the tropical regions (such as S. guyanense, S. javanicum, S. stuposum), as well as the types with restricted geographic distribution in S America are included in the study. Two new species from a little known subgenus Myochrotes, in which the cultivation is difficult, are described: S. papillicapitatum SANT'ANNA et KOMAREK and S. chorae SANT'ANNA et KomiatEx. Our analyses support the principle of congruency of morphological characters with phylogenetic position of the studied species.