Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 1990 [paraphyletic?]
             Superphylum "Proteobacteria" Craig et al. 2010
               Phylum "Alphaproteobacteria" Garrity et al., 2006 [monotypic]
                 Class Alphaproteobacteriaᵀ Garrity et al. 2006
                   Order Rickettsiales Gieszczykiewicz 1939 (Approved Lists 1980)
                     1 Genus Lyticum (ex Preer et al. 1974) Preer and Preer 1982, incertae sedis
                     2 Candidatus "Odyssella" incertae sedis [monotypic]
                     3 Genus Pseudocaedibacter Quackenbush 1982, incertae sedis
                     4 Genus Symbiotes Philip 1956 (Approved Lists 1980), incertae sedis [monotypic]
                     5 Genus Tectibacter (ex Preer et al. 1974) Preer and Preer 1982, incertae sedis [monotypic]
                     6 Family Rickettsiaceae Pinkerton 1936 (Approved Lists 1980)
                     7.1 Family Anaplasmataceae Philip 1957 (Approved Lists 1980)
                     7.2 Candidatus "Midichloria mitochondrii" Sassera et al. 2006
                     8 Family Holosporaceae Görtz and Schmidt 2006 [monotypic]