Domain Bacteria Woese et al. 1990
   Phylum Actinobacteria Garrity and Holt 2001
     Class Actinobacteria Stackebrandt et al. 1997
       Subclass Actinobacteridae Stackebrandt et al. 1997 see Class Actinobacteria Stackebrandt et al. 1997
         Order Actinomycetales Buchanan 1917 (Approved Lists 1980)
           Suborder Frankineae Stackebrandt et al. 1997 see Order Frankiales Sen et al. 2014
             Family Acidothermaceae Rainey et al. 1997
               1 Genus Acidothermus Mohagheghi et al. 1986