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 Negativicutes Marchandin et al. 2010 [monotypic] Order Selenomonadales Marchandin et al. 2010 Family Selenomonadaceaeᵀ Campbell et al. 2015 Genus Propionispira Schink et al. 1983 [monotypic] 1 Propionispira arborisᵀ Schink et al. 1983