prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Thermotogae" Reysenbach 2001 [monotypic]
       Class Thermotogae Reysenbach 2002
         Order Thermotogales Reysenbach 2002 [monotypic]
           Family Thermotogaceae Reysenbach 2002
             1 Genus Fervidobacterium Patel et al. 1985
             2 Genus Thermococcoides Feng et al. 2010
             3 Genus Thermosipho Huber et al. 1989
             4 Genus Thermotoga Stetter and Huber 1986