[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
         Order Rhodobacterales Garrity et al. 2006
           Family Rhodobacteraceae Garrity et al. 2006
             Genus Methylarcula Doronina et al. 2000
               1 Methylarcula marina Doronina et al. 2000
               2 Methylarcula terricola Doronina et al. 2000