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 Caldicellulosiruptor acetigenus (Nielsen et al. 1994) Onyenwoke et al. 2006