Procaryotic Genera Domain "Bacteria" Woese et al. 1990 Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005 Class "Alphaproteobacteria" Garrity and Holt 2001 nom. nud. see Class Alphaproteobacteria Garrity et al. 2006 Order Rickettsiales Gieszczykiewicz 1939 (Approved Lists 1980) Family Rickettsiaceae Pinkerton 1936 (Approved Lists 1980) Genus Rickettsia da Rocha-Lima 1916 (Approved Lists 1980)