prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Firmicutes" corrig. Gibbons and Murray 1978 (Approved Lists 1980)
       1 Class Bacilli Ludwig et al. 2010
       2 Class Clostridia Rainey 2010
       3 Class Erysipelotrichia Ludwig et al. 2010 [monotypic]
       4 Class Limnochordia Watanabe et al. 2015 [monotypic]
       5 Class Negativicutes Marchandin et al. 2010
       6 Class Thermolithobacteria Sokolova et al. 2007 [monotypic]
       7 Class Tissierellia Alauzet et al. 2014 [monotypic]