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 "Proteobacteria" Craig et al. 2010 Phylum "Alphaproteobacteria" Garrity et al., 2006 [monotypic] Class Alphaproteobacteriaᵀ Garrity et al. 2006 Order Rhodospirillales Pfennig and Trüper 1971 (Approved Lists 1980) Family Rhodospirillaceae Pfennig and Trüper 1971 (Approved Lists 1980) Genus Rhodospirillumᵀ Molisch 1907 (Approved Lists 1980) [monotypic] Rhodospirillum rubrum (Esmarch 1887) Molisch 1907 (Approved Lists 1980)