[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Alphaproteobacteria Garrity et al. 2006
         1 Order Rhodospirillales Pfennig and Trüper 1971 (Approved Lists 1980)
         2 Order Kordiimonadales Kwon et al. 2005
         3 Order Rickettsiales Gieszczykiewicz 1939 (Approved Lists 1980)
         4 Order Rhodobacterales Garrity et al. 2006
         5 Order Sphingomonadales Yabuuchi and Kosako 2006
         6 Order Caulobacterales Henrici and Johnson 1935 (Approved Lists 1980)
         7 Order Rhizobiales Kuykendall 2006
         8 Order "Parvularculales"