title: Cephalothrix gen. nov. (Cyanobacteria): towards an intraspecific phylogenetic evaluation by multilocus analyses.
abstract: 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.
authors.affiliation: Institute of Botany, Nucleus of Phycology, São Paulo, SP, Brazil.
authors.forename: Camila Francieli
authors.initials: CF
authors.lastname: da Silva Malone
authors.affiliation: Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, Brazil.
authors.forename: Janaína
authors.initials: J
authors.lastname: Rigonato
authors.affiliation: Laboratory of Bacterial Physiology and Genetics, Centre for Protein Engineering, University of Liège, Sart Tilman B6, Liège, Belgium.|Department of Arctic Biology, University Centre in Svalbard, Longyearbyen, Norway.
authors.forename: Haywood Dail
authors.initials: HD
authors.lastname: Laughinghouse
authors.affiliation: Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, Florianópolis, SC, Brazil.
authors.forename: Éder Carlos
authors.initials: ÉC
authors.lastname: Schmidt
authors.affiliation: Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, Florianópolis, SC, Brazil.
authors.forename: Zenilda Laurita
authors.initials: ZL
authors.lastname: Bouzon
authors.affiliation: Laboratory of Bacterial Physiology and Genetics, Centre for Protein Engineering, University of Liège, Sart Tilman B6, Liège, Belgium.
authors.forename: Annick
authors.initials: A
authors.lastname: Wilmotte
authors.affiliation: Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, Brazil.
authors.forename: Marli Fátima
authors.initials: MF
authors.lastname: Fiore
authors.affiliation: Institute of Botany, Nucleus of Phycology, São Paulo, SP, Brazil.
authors.forename: Célia Leite
authors.initials: CL
authors.lastname: Sant'Anna
mesh_terms: D000458:Cyanobacteria / Q000145:classification* / Q000166:cytology / Q000648:ultrastructure; D004269:DNA, Bacterial / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S