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 Negativicutes Marchandin et al. 2010 [monotypic]
                   Order Selenomonadales Marchandin et al. 2010
                     Family Selenomonadaceaeᵀ Campbell et al. 2015
                       Genus Selenomonasᵀ von Prowazek 1913 (Approved Lists 1980)
                         Selenomonas ruminantium (Certes 1889) Wenyon 1926 (Approved Lists 1980)
                           1 Selenomonas ruminantium subsp. lactilytica Bryant 1956 (Approved Lists 1980)
                           2 Selenomonas ruminantium subsp. ruminantiumᵀ (Certes 1889) Bryant 1956 (Approved Lists 1980)