[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       1 Class Alphaproteobacteria Garrity et al. 2006
       2 Class Betaproteobacteria Garrity et al. 2006
       3 Class Gammaproteobacteria Garrity et al. 2005
       4 Class Deltaproteobacteria Kuever et al. 2006
       5 Class Epsilonproteobacteria Garrity et al. 2006