prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Epsilonproteobacteria Garrity et al. 2006
         Order Campylobacterales Garrity et al. 2006
           1 Family "Hydrogenimonaceae" Garrity et al. 2004 nom. nud. [monotypic]
           2 Family Campylobacteraceae Vandamme and De Ley 1991
           3 Family Helicobacteraceae Garrity et al. 2006