Table 2. A higher-level classification scheme for the Alphaproteobacteria and the Magnetococcia classes within the Proteobacteria, and the Rickettsiales and Rhodospirillales orders within the Alphaproteobacteria.

Class 1. Alphaproteobacteria Garrity et al., 2005

Subclass 1. Rickettsidae Ferla et al., 2013 emend. Muñoz-Gómez et al. 2019 (this work)

Order 1. Rickettsiales Gieszczkiewicz, 1939 emend. Dumler et al., 2001

Family 1. Anaplasmataceae Philip, 1957                                           Family 2. 'Candidatus Midichloriaceae' Montagna et al., 2013                                           Family 3. Rickettsiaceae Pinkerton, 1936

Subclass 2. Caulobacteridae Ferla et al., 2013 emend. Muñoz-Gómez et al. 2019

Order 1. Rhodospirillales Pfennig and Trüper, 1971 emend. Muñoz-Gómez et al. 2019

Family 1. Acetobacteraceae (ex Henrici 1939) Gillis and De Ley, 1980                                           Family 2. Rhodospirillaceae Pfennig and Trüper, 1971 emend. Muñoz-Gómez et al. 2019                                           Family 3. Azospirillaceae fam. nov. Muñoz-Gómez et al. 2019                                           Family 4. Holosporaceae Szokoli et al., 2016                                           Family 5. Rhodovibriaceae fam. nov. Muñoz-Gómez et al. 2019                                           Family 6. Geminicoccaceae Proença et al., 2018

Order 2. Sneathiellales Kurahashi et al., 2008

Order 3. Sphingomonadales Yabuuchi and Kosako, 2005

Order 4. Pelagibacterales Grote et al., 2012

Order 5. Rhodobacterales Garrity et al., 2005

Order 6. Caulobacterales Henrici and Johnson, 1935

Order 7. Rhizobiales Kuykendall, 2005

Class 2. Magnetococcia Parks et al., 2018

Order 1. Magnetococcales Bazylinski et al., 2013