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 Halanaerobiales corrig. Rainey and Zhilina 1995
                     Family Halanaerobiaceaeᵀ corrig. Oren et al. 1984
                       1 Genus Halanaerobiumᵀ corrig. Zeikus et al. 1984
                       2 Genus Halarsenatibacter Switzer Blum et al. 2010 [monotypic]
                       3 Genus Halocella Simankova et al. 1994 nom. illeg. [monotypic]
                       4 Genus Halonatronomonas Boltyanskaya et al. 2023
                       5 Genus Halothermothrix Cayol et al. 1994 [monotypic]
                       6 Genus Iocasia Zhang et al. 2025