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)
                 Class Clostridia Rainey 2010
                   Order Clostridialesᵀ Prévot 1953 (Approved Lists 1980)
                     Family Ruminococcaceae Rainey 2010
                       Genus Anaerobacterium Horino et al. 2014 [monotypic]
                       Genus Hydrogenoanaerobacterium Song and Dong 2009
                       Genus Pseudobacteroides Horino et al. 2014
                       1 Genus Ercella van Gelder et al. 2014 [monotypic]
                       2 Genus Ethanoligenens Xing et al. 2006 [monotypic]
                       3.1 Genus Acetanaerobacterium Chen and Dong 2004 [monotypic]
                       3.2 Genus Acetivibrio Patel et al. 1980
                       3.3 Genus Anaerotruncus Lawson et al. 2004 [monotypic]
                       3.4 Genus Faecalibacterium Duncan et al. 2002 [monotypic]
                       3.5 Genus Fastidiosipila Falsen et al. 2005 [monotypic]
                       3.6 Genus Sporobacter Grech-Mora et al. 1996 [monotypic]
                       3.7 Genus Subdoligranulum Holmstrøm et al. 2004 [monotypic]
                       4.1 Genus Anaerofilum Zellner et al. 1996
                       4.2 Genus Ruminococcusᵀ Sijpesteijn 1948 (Approved Lists 1980)
                       5 Genus Papillibacter Defnoun et al. 2000 [monotypic]
                       6.1 Genus Oscillibacter Iino et al. 2007
                       6.2 Genus Oscillospira Chatton and Pérard 1913 (Approved Lists 1980) [monotypic]