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. 2024
             Kingdom Bacillatiᵀ (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Bacillotaᵀ Gibbons and Murray 2021
                 Class Clostridia Rainey 2010
                   Order Thermoanaerobacterales Wiegel 2010
                     1 Genus Calorimonas Khomyakova et al. 2020, incertae sedis
                     2 Family Mahellaceae Chuvochina et al. 2024 [monotypic]
                     3 Family Thermoanaerobacteraceaeᵀ Wiegel 2010
                     4 Family Thermodesulfobiaceae Mori et al. 2004 [monotypic]
                     5 Family Zhaonellaceae Lv et al. 2020 [monotypic]
                     6 Family "Candidatus Desulforudaceae" Chuvochina et al. 2023 nom. pro-inval.