RT Journal Article SR Electronic(1) A1 da Silva Malone, Camila Francieli A1 Rigonato, Janaína A1 Laughinghouse, Haywood Dail A1 Schmidt, Éder Carlos A1 Bouzon, Zenilda Laurita A1 Wilmotte, Annick A1 Fiore, Marli Fátima A1 Sant'Anna, Célia LeiteYR 2015 T1 Cephalothrix gen. nov. (Cyanobacteria): towards an intraspecific phylogenetic evaluation by multilocus analyses JF International Journal of Systematic and Evolutionary Microbiology, VO 65 IS Pt_9 SP 2993 OP 3007 DO https://doi.org/10.1099/ijs.0.000369 PB Microbiology Society, SN 1466-5034, AB For more than a decade, the taxonomy of the Phormidiaceae has been problematic, since morphologically similar organisms represent phylogenetically distinct entities. Based on 16S rRNA gene sequence analyses, the polyphyletic genus Phormidium and other gas-vacuolated oscillatorioids appear scattered throughout the cyanobacterial tree of life. Recently, several studies have focused on understanding the oscillatorioid taxa at the generic level. At the specific level, few studies have characterized cyanobacterial strains using combined datasets (morphology, ultrastructure and molecular multilocus analyses). Using a multifaceted approach, we propose a new, well-defined genus, Cephalothrix gen. nov., by analysing seven filamentous strains that are morphologically ‘intermediate’ between gas-vacuolated taxa and Phormidium. Furthermore, we characterize two novel species: Cephalothrix komarekiana sp. nov. (strains CCIBt 3277, CCIBt 3279, CCIBt 3523, CCALA 155, SAG 75.79 and UTEX 1580) and Cephalothrix lacustris sp. nov. (strain CCIBt 3261). The generic name and specific epithets are proposed under the provisions of the International Code of Nomenclature for Algae, Fungi, and Plants., UL https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.000369