Cephalothrix gen. nov. (Cyanobacteria): towards an intraspecific phylogenetic evaluation by multilocus analyses

Int J Syst Evol Microbiol. 2015 Sep;65(9):2993-3007. doi: 10.1099/ijs.0.000369. Epub 2015 Jun 1.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyanobacteria / classification*
  • Cyanobacteria / cytology
  • Cyanobacteria / ultrastructure
  • DNA, Bacterial / genetics
  • DNA, Ribosomal Spacer / genetics
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics
  • Sequence Analysis, DNA


  • DNA, Bacterial
  • DNA, Ribosomal Spacer
  • RNA, Ribosomal, 16S