Acidithiobacillia Williams and Kelly 2013 Acidithiobacillia Williams and Kelly 2013 Acidithiobacillales Garrity et al. 2005 Universal Root Woese et al. 1990 Bacteria (None 2015) Woese et al. 1990 Proteobacteria (sic) Garrity et al. 2021 Pseudomonadota corrig. Garrity et al. 2021 Alphaproteobacteriota (sic) Garrity et al. 2021 Acidithiobacillia Williams and Kelly 2013 Proteobacteria (sic) Garrity et al. 2021 Pseudomonadota corrig. Garrity et al. 2021 Alphaproteobacteriota (sic) Garrity et al. 2021 Gammaproteobacteria Garrity et al. 2005 emend. Williams and Kelly 2013 Betaproteobacteria Garrity et al. 2006 emend. Boden et al. 2017 Deltaproteobacteria Kuever et al. 2006 emend. Hahn et al. 2017 Alphaproteobacteria Garrity et al. 2006 Epsilonproteobacteria Garrity et al. 2006 Zetaproteobacteria (sic) Makita et al. 2017 Mariprofundia corrig. Makita et al. 2017 Oligoflexia Nakai et al. 2014 emend. Waite et al. 2020 Hydrogenophilalia Boden et al. 2017 Deltabacteria Cavalier-Smith 2002 Acidithiobacillales Garrity et al. 2005 Williams K.P. Kelly D.P. Proposal for a new class within the phylum Proteobacteria, Acidithiobacillia classis nov., with the type order Acidithiobacillales, and emended description of the class Gammaproteobacteria 2013 63 8 2901 2906 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijs.0.049270-0 23334881 Williams K.P. Kelly D.P. Proposal for a new class within the phylum Proteobacteria, Acidithiobacillia classis nov., with the type order Acidithiobacillales, and emended description of the class Gammaproteobacteria 2013 63 8 2901 2906 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijs.0.049270-0 23334881