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 Gammaproteobacteria Garrity et al. 2005
         Order Legionellales Garrity et al. 2005
           1 Family Coxiellaceae Garrity et al. 2005
           2 Family Legionellaceae Brenner et al. 1979 (Approved Lists 1980)
           3 Genus Rickettsiella Philip 1956 (Approved Lists 1980), incertae sedis