Bloom-forming and other planktonic Anabaena (Cyanobacteria) morphospecies with twisted trichomes from Rio Grande do Sul State, Brazil
Werner, Vera Regina; Laughinghouse, Haywood Dail IV
Many planktonic Anabaena with twisted trichomes are morphologically similar leading to improper identification, especially as A. spiroides. However, many studies have shown differences among them, and several distinguishable species have been described. This study aimed at the taxonomic analysis of natural populations, contributing to the knowledge of the diversity and distribution of Anabaena in subtropical and temperate environments of southern Brazil. Based on the morphology of populations from different water bodies in Rio Grande do Sul State, emphasizing on those reported in blooms from reservoirs supplying public drinking water, nine taxa were recognized. Six morphospecies were forming blooms, among them, five were found toxic. Anabaena mucosa and A. nygaardii are reported for the first time in continental America and A. mendotae for South America. This study correctly identifies A. oumiana for the first time in South America with descriptions, illustrations, and comments. Descriptions, critical analyses of taxonomic features for specific delimitation, measurements, and illustrations of the taxa are presented. Since this study was based on morphology, we consider that further research will be carried out based on ultra-structure and genetic traits.