Cyanoaggregatum brasiliense gen. et sp. nov., a new chroococcal Cyanobacteria from Southern Brazil

Abstract

-(Cyanoaggregatum brasiliense gen. et sp. nov., a new chroococcal Cyanobacteria from Southern Brazil). The paper proposed Cyanoaggregatum brasiliense, a new genus and species from the plankton of a subtropical brackish coastal lagoon from Rio Grande do Sul State, South Brazil. It differs from all other members of Chroococcales by its characteristic arrangement of cells in irregular groups distributed in a single, flat or slightly curved layer, on irregular rows, slightly distant from each other, forming a mosaic-like pattern slightly below the surface of the mucilaginous colonial envelope. The cell division in one plane perpendicular to the long axis and the lack of pseudo-filaments indicate its classification in the family Synechococcaceae, sub-family Aphanothecoideae. The general characteristics, the diagnostic criteria and the taxonomic position are discussed, and a comparison between Cyanoaggregatum and its most closely related genera is presented. Physical and chemical data on the studied lagoon and geographical distribution are presented.Key words -coastal lagoon, Cyanoaggregatum brasiliense, Cyanobacteria, new genus and species, southern Brazil RESUMO -(Cyanoaggregatum brasiliense gen. et sp. nov., uma nova cianobactéria (Chroococcales) do sul do Brasil). O trabalho propõe Cyanoaggregatum brasiliense, gênero e espécie novos, encontrado no plâncton de lagoa costeira salobra, subtropical, do Estado do Rio Grande do Sul, sul do Brazil. O novo gênero difere dos demais membros da ordem Chroococcales pela disposição característica de suas células em grupos irregulares, planos ou levemente curvos, constituídos por uma camada de células, dispostas em fileiras irregulares, levemente distantes umas das outras, formando padrão semelhante a um mosaico, na periferia do envelope mucilaginoso. A divisão celular em um único plano, perpendicular ao eixo maior e a ausência de pseudofilamentos permitiram classificar estas populações na família Synechococcaceae, subfamília Aphanothecoideae. As características gerais, a diagnose e a posição taxonômica do novo táxon são discutidas. São apresentadas comparações entre Cyanoaggregatum e os gêneros mais próximos, assim como dados físicos e químicos referentes ao local-tipo e sua distribuição geográfica.Palavras-chave -Cyanoaggregatum brasiliense, Cyanobacteria, gênero e espécie novos, lagoa costeira, sul do Brasil

Phylogenetic and taxonomic delimitation of the cyanobacterial genusAphanotheceand description ofAnathece gen. nov.

“…Other taxa that must be investigated at the generic level are Aphanothece caldariorum (with characteristic rod-like cells and granules at the cell poles; cf. Geitler, 1932;Maresˇ, 2010) and Cyanoaggregatum (Werner et al, 2008).…”

“…1). Lastly, the genus Cyanoaggregatum which differs by the special arrangement of cells in colonies, was recently described (Werner et al, 2008), using morphological and ecological criteria to separate it from Aphanothece.…”

Cyanobacteria from coastal lagoons in southern Brazil: non-heterocytous filamentous organisms

“…Freshwater habitats in subtropical Brazil are relatively poorly known from a phycological perspective, although freshwater cyanobacteria from Rio Grande do Sul State have been documented by Callegaro et al (1981), Torgan et al (1981Torgan et al ( , 1995, Franceschini (1983Franceschini ( , 1990, Werner (1984Werner ( , 1988Werner ( , 2002, Torgan & Garcia (1989), Werner & Rosa (1992), Torgan & Paula (1994), Garcia & Vélez (1995), Torgan (1997), Werner & Sant'Anna (1998, 2006, Cardoso & Motta-Marques (2003, Carvalho et al (2008), Werner et al (2008), and Werner & Laughinghouse (2009)…”

Lagosinema tenuis gen. et sp. nov. (Prochlorotrichaceae, Cyanobacteria): a new brackish water genus from Tropical Africa

“…Studies of cyanobacteria using a polyphasic approach have led to discovery of novel species and genera in tropical regions. For example, a particularly active cyanobacterial research group in Brazil have described a number of new genera from the Mata Atlantica and other parts of Brazil, including Brasilonema Fiore et al (2007), Cyanoaggregatum Werner et al (2008) Genuário et al (2015), Alkalinema Vaz et al (2015), Pantanalinema Vaz et al (2015), Dapisiostemon Hentschke et al (2016), Komarekiella Hentschke et al (2017), Potamolinea Martins & Branco (2016), and Phyllonema Alvarenga et al (2016). All of these new genera were described just in the past decade, and there is little evidence to suggest that many new additional genera will not be described from this part of the world in the near future.…”