prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Aquificae" Reysenbach 2001 [monotypic]
       Class Aquificae Reysenbach 2002 [monotypic]
         Order Aquificales Reysenbach 2002
           Family Desulfurobacteriaceae L'Haridon et al. 2006
             Genus Desulfurobacterium L'Haridon et al. 1998