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 Thermoanaerobacterales Wiegel 2010
                     Genus Caldicellulosiruptor Rainey et al. 1995, incertae sedis
                       1 Caldicellulosiruptor acetigenus (Nielsen et al. 1994) Onyenwoke et al. 2006
                       2 Caldicellulosiruptor bescii Yang et al. 2010
                       3 Caldicellulosiruptor hydrothermalis Miroshnichenko et al. 2008
                       4 Caldicellulosiruptor kristjanssonii Bredholt et al. 1999
                       5 Caldicellulosiruptor kronotskyensis Miroshnichenko et al. 2008
                       6 Caldicellulosiruptor lactoaceticus Mladenovska et al. 1997
                       7 "Caldicellulosiruptor obsidiansis" Hamilton-Brehm et al. 2010
                       8 Caldicellulosiruptor owensensis Huang et al. 1998
                       9 Caldicellulosiruptor saccharolyticusᵀ Rainey et al. 1995