Cephalothrix gen. nov. (Cyanobactérie): une évaluation phylogénétique intraspécifique par analyse multilocus

For more than a decade, the taxonomy of Phormidiaceae has been problematic, since morphologically similar organisms represent phylogenetically distinct entities. Based on 16S rRNA 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, there are few studies characterizing cyanobacterial strains using combined datasets (morphology, ultrastructure, and molecular multi-locus analyses). Using a multi-facet approach, we propose a new, well-defined genus, Cephalothrix gen. nov., by analyzing seven filamentous strains morphologically 'intermediate' between gas-vacuolated taxa and Phormidium. Furthermore, we characterize two new species: Cephalothrix komarekiana (CCIBt 3277, CCIBt 3279, CCIBt 3523, CCALA 155, SAG 75.79, and UTEX 1580) and Cephalothrix lacustris (CCIBt 3261). The generic name and specific epithets were proposed under the provisions of the International Code of Nomenclature for algae, fungi, and plants