Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 1990 [paraphyletic?]
             Superphylum Terrabacteria Battistuzzi et al. 2004
               Phylum Firmicutes corrig. Gibbons and Murray 1978 (Approved Lists 1980)
                 Genus "Desulforudis" Chivian et al. 2008 [monotypic]
                 Class Limnochordia Watanabe et al. 2015 [monotypic]
                 Class Mollicutes Edward and Freundt 1967 (Approved Lists 1980)
                 Class Tissierellia Alauzet et al. 2014 [monotypic]
                 1.1 Class Clostridia Rainey 2010
                 1.1.0 [Class "Clostridia" Garrity et al. 2001 nom. ined.] see Class Clostridia Rainey 2010
                 1.2 Class Negativicutes Marchandin et al. 2010 [monotypic]
                 2 Class Erysipelotrichia Ludwig et al. 2010 [monotypic]
                 2.0 [Class "Erysipelotrichi" nom. inval. [monotypic]] see Class Erysipelotrichia Ludwig et al. 2010
                 3 Class Bacilli Ludwig et al. 2010
                 3.0 [Class "Bacilli" Garrity et al. 2001 nom. ined.] see Class Bacilli Ludwig et al. 2010
                 3.0 [Class Firmibacteria Murray 1988] see Class Bacilli Ludwig et al. 2010
                 4 Class Thermolithobacteria Sokolova et al. 2007 [monotypic]