This article lists the orders of the Bacteria. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) and the phylogeny is based on 16S rRNA-based LTP release 132 by The All-Species Living Tree Project.
Phylogeny
National Center for Biotechnology Information (NCBI) taxonomy was initially used to decorate the genome tree via tax2tree. The 16S rRNA-based Greengenes taxonomy is used to supplement the taxonomy particularly in regions of the tree with no cultured representatives. List of Prokaryotic names with Standing in Nomenclature (LPSN) is used as the primary taxonomic authority for establishing naming priorities. Taxonomic ranks are normalised using phylorank and the taxonomy manually curated to remove polyphyletic groups.
Cladogram was taken from GTDB release 10-RS226 (16th April 2025).
- Class "Bathosphaeria" <small>Mehrshad et al. 2018</small>
- ?"Bathosphaerales" <small>Mehrshad et al. 2018</small> [JG30-KF-CM66]
- Class "Martimicrobia" <small>Williams et al. 2024</small>
- ?"Martimicrobiales" <small>Williams et al. 2024</small>
- Class "Poriflexia" <small>Kogawa et al. 2022</small>
- ?"Ca. Poriflexus" <small>Kogawa et al. 2022</small>
- Class "Spiritibacteria" <small>Williams et al. 2024</small>
- ?"Spiritibacterales" <small>Williams et al. 2024</small>
- Class "Tarhunnaeia" <small>Williams et al. 2024</small>
- ?"Tarhunnaeales" <small>Williams et al. 2024</small>
- Class "Uliximicrobia" <small>Williams et al. 2024</small>
- ?"Uliximicrobiales" <small>Williams et al. 2024</small>
- Class "Umbricyclopia" <small>Mehrshad et al. 2018</small>
- ?"Umbricyclopales" <small>Mehrshad et al. 2018</small> (TK10)
- Class "Dormiibacteria" <small>(sic) Montgomery et al. 2021</small> (AD3)
- "Aeolococcales" <small>Montgomery et al. 2021</small>
- "Dormibacterales" <small>(sic) Montgomery et al. 2021</small>
- Class "Limnocylindria" <small>Mehrshad et al. 2018</small>
- "Limnocylindrales" <small>Mehrshad et al. 2018</small> (SL56)
- Class Ktedobacteria <small>corrig. Cavaletti et al. 2007</small>
- Ktedobacterales <small>corrig. Cavaletti et al. 2007</small> (Thermogemmatisporales)
- Class Chloroflexia <small>Gupta et al. 2013</small>
- Chloroflexales <small>Gupta et al. 2013</small> (Herpetosiphonales, Kallotenuales)
- "Chloroheliales" <small>Tsuji et al. 2024</small>
- "Thermobaculales" <small>Chuvochina et al. 2023</small>
- Thermomicrobiales <small>Garrity & Holt 2002</small> (Sphaerobacterales)
- Class Dehalococcoidia <small>Löffler et al. 2013</small>
- "Australimonadales" <small>Prabhu et al. 2024</small> [UBA2963]
- Dehalococcoidales <small>Löffler et al. 2013</small>
- "Lucifugimonadales" <small>Lim et al. 2023</small> [UBA1151]
- "Monstramariales" <small>Landry et al. 2017</small> [UBA11650; UBA3495]
- Tepidiformales <small>Kochetkova et al. 2020</small>
- Class "Caldilineia" <small>Oren, Parte & Garrity 2016 ex Cavalier-Smith 2020</small>
- Aggregatilineales <small>Nakahara et al. 2019</small> ("Phototrophicales")
- "Amarolineaceae" <small>Andersen et al. 2019</small> {SSC4}
- Anaerolineales <small>Yamada et al. 2006</small>
- Ardenticatenales <small>Kawaichi et al. 2013</small>
- Caldilineales <small>Yamada et al. 2006</small>
- "Epilineales" <small>Petriglieri et al. 2023</small>
- "Roseilineaceae" <small>Ward et al. 2021</small> {J036}
- "Promineifilales" <small>corrig. Chuvochina et al. 2023</small>
- Thermoflexales <small>Dodsworth et al. 2014</small>
- Class "Sysuimicrobiia" <small>Liu et al. 2024</small> [CSP1-3]
- "Sysuimicrobiales" <small>Liu et al. 2024</small>
- Class "Zipacnadia" <small>Carlton et al. 2023</small> (UBA5377)
- "Zipacnadales" <small>Carlton et al. 2023</small>
- Class Abditibacteriia <small>Tahon et al. 2018</small> (FBP)
- Abditibacteriales <small>Tahon et al. 2018</small>
- Class Fervidibacteria <small>Nou et al. 2025</small>
- Fervidibacterales <small>Nou et al. 2025</small>
- Class "Heboniibacteriia" <small>corrig. Carlton et al. 2023</small> (CAIYQO01)
- "Heboniibacterales" <small>corrig. Carlton et al. 2023</small>
- Class UBA5829
- "Candidatus Hippobium" <small>Gilroy et al. 2022</small> {UBA5829: UBA5829}
- Class Fimbriimonadia <small>Im et al. 2012</small>
- Fimbriimonadales <small>Im et al. 2012</small>
- Class Chthonomonadia <small>Oren, Parte & Garrity 2016</small>
- Chthonomonadales <small>Lee et al. 2011</small>
- Class Armatimonadia <small>Tamaki et al. 2011</small> (OP10)
- Armatimonadales <small>Tamaki et al. 2011</small> (Capsulimonadales)
- Class "Eudoremicrobiia" <small>(sic) Paoli et al. 2022</small>
- ?"Eudoremicrobiales" <small>(sic) Paoli et al. 2022</small>
- Class "Xenobia" <small>Ji et al. 2021</small> (UBP9)
- "Xenobiales" <small>Ji et al. 2021</small>
- Class Vulcanimicrobiia <small>Yabe et al. 2024</small> (WPS2)
- "Eremiobacterales" <small>Ward, Cardona & Holland-Moritz 2019</small>
- Vulcanimicrobiales <small>Yabe et al. 2024</small> ("Baltobacterales"; "Palusbacterales"; "Rubrimentiphilales")
Firmicutes incertae sedis
Clade Bacillota G
- Class Limnochordia <small>Watanabe, Kojima & Fukui 2015</small>
- Limnochordales <small>Watanabe, Kojima & Fukui 2015</small>
- Class "Hydrogenisporia" <small>Pallen, Rodriguez-R & Alikhan 2022</small>
- "Capillibacteriales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [UBA10575]
- "Hydrogenisporales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [UBA8346]
Clade Bacillota E
- Class UBA3575
- "Candidatus Acetocimmeria" Smith et al. 2021 {UBA3575: UBA3575}
- Class Thermaerobacteria <small>Chuvochina et al. 2024</small>
- Thermaerobacterales <small>Chuvochina et al. 2024</small>
- Class Symbiobacteriia <small>Chuvochina et al. 2024</small>
- Symbiobacteriales <small>Chuvochina et al. 2024</small>
- Class "Fermentithermobacillia" <small>Kadnikov et al. 2023</small>
- "Fermentithermobacillales" <small>Kadnikov et al. 2023</small>
- Class Sulfobacillia <small>Chuvochina et al. 2024</small>
- Sulfobacillales <small>Chuvochina et al. 2024</small>
Clade "Selenobacteria"
- Class Peptococcia <small>Chuvochina et al. 2024</small>
- Peptococcales <small>Chuvochina et al. 2024</small>
- "Thermanaerosceptrales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DRI-13]
- Class "Thermacetogeniia" <small>corrig. Voyron et al. 2022</small>
- Thermacetogeniales <small>Chuvochina et al. 2024</small>
- Class Syntrophomonadia <small>Chuvochina et al. 2024</small>
- Syntrophomonadales <small>Chuvochina et al. 2024</small>
- Class DSM-16504
- Desulfitibacterales <small>Chuvochina et al. 2024</small>
- Class KKC1
- Calderihabitantales <small>Chuvochina et al. 2024</small>
- Class JADQBR01
- "Metallumcola" <small>Hsu et al. 2024</small> {JADQBR01: JADQBR01}
- Class DULZ01
- Zhaonellaceae <small>Lv et al. 2020</small> {DULZ01}
- Class "Moorellia" <small>Sorokin et al. 2020</small>
- Neomoorellales <small>Gtari & Ventura 2025</small>
- Class "Dehalobacteriia"
- "Avidehalobacterales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [UBA4068]
- "Cryptoclostridiales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [UBA7702]
- "Dehalobacteriales"
- Class Desulfitobacteriia <small>Chuvochina et al. 2024</small>
- Desulfitobacteriales <small>Chuvochina et al. 2024</small>
- "Heliobacteriales" <small>Kinman 1994 ex Cavalier-Smith 2020</small>
- Class "Carboxydocellia" <small>Pallen, Rodriguez-R & Alikhan 2022</small>
- "Carboxydocellales <small>Chuvochina et al. 2024</small>
- Class Thermincolia <small>Chuvochina et al. 2024</small>
- "Thermincolales <small>Chuvochina et al. 2024</small>
- Class "Carboxydothermia" <small>Pallen, Rodriguez-R & Alikhan 2022</small>
- Carboxydothermales <small>Chuvochina et al. 2024</small>
- Class Desulfotomaculia <small>Chuvochina et al. 2024</small>
- Ammonificales <small>corrig. Chuvochina et al. 2024</small>
- Desulfotomaculales <small>Chuvochina et al. 2024</small>
- Class "Halanaerobiia" <small>Cavalier-Smith 2020</small>
- "Anoxybacterales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> {DY22613}
- Halanaerobiales <small>corrig. Rainey & Zhilina 1995</small>
- Halobacteroidales <small>Chuvochina et al. 2024</small>
Clade "Clostridiota"
Clade Bacillota D
- Class "Proteinivoracia"
- "Proteinivoracales"
- Class Dethiobacteria <small>Sorokin & Merkel 2025</small>
- "Candidatus Contubernalis" <small>corrig. Zhilina et al. 2005</small> {SKNC01: SKNC01}
- Dethiobacterales <small>Sorokin & Merkel 2025</small>
- Class Natranaerobiia <small>Chuvochina et al. 2024</small>
- Natranaerobiales <small>Mesbah et al. 2007</small>
Clade Cyanoprokaryota
- Class "Sericytochromatia" <small>Soo et al. 2017</small>
- S15B-MN24 ["Sericytochromatia"; "Tanganyikabacteria"]
- UBA7694 ["Blackallbacteria"]
- Class Vampirovibrionia <small>Chuvochina et al. 2024</small>
- "Caenarcaniphilales" <small>Soo et al. 2014</small>
- "Gastranaerophilales" <small>Di Rienzi et al. 2013</small>
- "Obscuribacterales" <small>Soo et al. 2014</small>
- Vampirovibrionales <small>Chuvochina et al. 2024</small>
- Class Gloeobacteria <small>Cavalier-Smith 2002</small>
- Gloeobacterales <small>Cavalier-Smith 2002</small>
- Class Phycobacteria <small>Cavalier-Smith 2002</small>
- Acaryochloridales <small>Miyashita et al. 2003 ex Strunecký & MareÃ
¡ 2022</small> ("Thermosynechococcales")
- ?Aegeococcales <small>Strunecký & MareÃ
¡ 2022</small>
- Trichothermofontia <small>Daroch et al. 2023</small> {B231}
- Cyanobacteriales <small>Rippka & Cohen-Bazire 1983</small> (Chamaesiphonales, Chroococcales, Chroococcidiopsidales, Coleofasciculales, Desertifilales, Nostocales, Oscillatoriales, Pleurocapsales, Spirulinales, Stigonematales)
- ?"Eurycoccales"
- ?Geitlerinematales <small>Strunecký & MareÃ
¡ 2022</small>
- Gloeoemargaritales <small>Moreira et al. 2016</small>
- Leptolyngbyales <small>Strunecký & MareÃ
¡ 2022</small>
- ?"Limnotrichales" <small>Trebuch et al. 2020</small>
- Neosynechococcales <small>Chuvochina et al. 2024</small>
- Nodosilineales <small>Strunecký & MareÃ
¡ 2022</small> (Phormidesmidales)
- Oculatellales <small>Strunecký & MareÃ
¡ 2022</small> (Elainellales)
- Prochlorococcaceae <small>Komárek & Strunecky 2020</small> {"PCC-6307"}
- Prochlorotrichales <small>Strunecký & MareÃ
¡ 2022</small> [PCC-9006]
- Pseudanabenales <small>Hoffmann, Komárek & Kastovsky 2005</small>
- ?"Pseudophormidiales"
- Romeriopsis <small>Hentschke et al. 2022</small> {JAAFJU01: JAAFJU01}
- Synechococcales <small>Hoffmann, Komárek & Kastovsky 2005</small>
- Thermostichales <small>Komárek & Strunecký 2020</small>
- Trichocoleaceae <small>Mai & Johansen 2018 non Nakai</small> {FACHB-46}
- Class Atribacteria <small>Katayama et al. 2021</small> (OP9)
- Atribacterales <small>Katayama et al. 2021</small> ("Caldatribacteriales")
- Class "Phoenicimicrobiia" <small>Jiao et al. 2024</small> (JS1)
- "Phoenicimicrobiales" <small>Jiao et al. 2024</small> (SB-45)
- Class "Thermodesulfobiia" <small>Frolov et al. 2023</small>
- "Thermodesulfobiales" <small>Cavalier-Smith 2023</small>
- Class HKB111
- "Candidatus Lithacetigena" <small>Nobu et al. 2022</small> {HKB111: HKB111}
- Class "Thermotogia" <small>Oren, Parte & Garrity 2016 ex Cavalier-Smith 2020</small>
- Mesoaciditogales <small>Itoh et al. 2016</small>
- Petrotogales <small>Bhandari & Gupta 2014</small> (Kosmotogales)
- Thermotogales <small>Reysenbach 2002 emend. Bhandari & Gupta 2014</small>
- Class "Bipolaricaulia" <small>Chuvochina et al. 2023</small>
- "Bipolaricaulales" <small>Chuvochina et al. 2023</small> (KB1 group, OP1)
- "Fraserbacterales" [GTDB tag: RIF31; RBG-16-55-9]
- Class Fusobacteriia <small>corrig. Staley & Whitman 2012</small>
- Fusobacterales <small>Staley & Whitman 2012</small> ("Bactepneumoniales")
- Class "Elulimicrobiia" <small>Rodriguez-R et al. 2020</small>
- ?"Elulimicrobiales" <small>Rodriguez-R et al. 2020</small>
- Class "Wirthbacteria"
- Class "Dojkabacteria" (WS6)
- Class "Katanobacteria" (WWE3)
- Class "Microgenomatia"
- Clade GWA2-44-7
- "Chazhemtobacteriales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [UBA1400]
- "Curtissbacterales"
- "Daviesbacterales"
- "Gottesmanbacterales"
- "Levybacterales"
- "Roizmanbacterales"
- "Shapirobacterales"
- "Woykebacterales" (RIF34)
- Class "Absconditabacteria"
- "Absconditabacterales" <small>(sic)Yakimov et al. 2022</small> (SR1)
- "Candidatus Altimarinus" <small>Rinke et al. 2013</small> {BD1-5: UBA6164} (GN02)
- Class "Gracilibacteria"
- "Abawacabacterales" (RIF46)
- "Fertabacterales" (DOLZORAL124_38_8; "Fallacibacteriota")
- "Peregrinibacterales" (PER)
- "Peribacterales" <small>Anantharaman et al. 2016</small>
- Class "Berkelbacteria" (ACD58)
- Class "Kazanbacteria" (Kazan)
- Class "Howlettbacteria" (CPR2)
- Class "Saccharimonadia" <small>corrig. Lemos et al. 2019</small> (TM7)
- "Saccharimonadales" <small>corrig. Lemos et al. 2019 ex Chuvochina et al. 2023</small>
- Class ?"Baikalibacteria" <small>Haro-Moreno et al. 2023</small>
- Class "Andersenbacteria" (RIF9)
- Class "Doudnabacteria" (SM2F11)
- Class "Torokbacteria" (GCA-2792135)
- Class "Patescibacteriia" <small>Dutkiewicz et al. 2025</small>
- ?"Brownbacterales"
- "Buchananbacterales" (sic) (RIF37)
- "Falkowbacterales" (sic)
- "Jacksonbacterales" (sic) (RIF38)
- "Kerfeldbacterales" (sic) (RIF4)
- "Komeilibacterales" (sic) (RIF6)
- "Kuenenbacterales" (sic)
- "Magasanikbacterales"
- "Moisslbacterales" [UBA2591]
- "Patescibacteriales" <small>Dutkiewicz et al. 2025</small>
- "Uhrbacterales"
- "Veblenbacterales" (RIF39)
- Class Minisyncoccia <small>Nakajima et al. 2025</small>
- Clade UBA6257
- "Azambacterales" (sic)
- "Giovannonibacteraceae" (sic) {UBA11713}
- ?"Montesolbacterales"
- "Moranbacterales" (OD1-i)
- "Niyogibacteraceae" (RIF11; HO2-45-28)
- Minisyncoccales <small>Nakajima et al. 2025</small> ["Paceibacterales" <small>Chuvochina et al. 2023</small>]
- "Parcunitrobacterales" <small>Castelle et al. 2017</small>
- "Portnoybacterales" (RIF22)
- "Ryanbacterales" (RIF10)
- "Spechtbacterales" (RIF19)
- "Sungbacterales" (RIF17)
- "Tagabacterales" (RIF12)
- "Terrybacteraceae" {JAHISW01} (RIF13)
- "Yanofskybacterales" (sic) (2-02-FULL-40-12)
Clade
Incertae sedis
- Class "Muiribacteriia" <small>corrig. Chuvochina et al. 2023</small>
- "Muiribacteriales" <small>corrig. Chuvochina et al. 2023</small>
- Class "Ozemibacteria" <small>corrig. Kadnikov et al. 2018</small> (RIF32/ACD39)
- "Ozemibacterales" <small>corrig. Kadnikov et al. 2018</small>
- Class "Wallbacteriia" [UBA9980] (RIF33)
- Class "Macinerneyibacteriia" <small>corrig. Yadav et al. 2020</small>
- "Macinerneyibacteriales" <small>corrig. Yadav et al. 2020</small>
- Class "Babeliae" <small>(sic) Yeoh et al. 2016</small> (TM6)
- "Babelales" <small>corrig. Yeoh et al. 2016</small>
- Class Leptospiria <small>Chuvochina et al. 2024</small>
- Leptospirales <small>corrig. Gupta et al. 2014</small>
- Turneriellales <small>Chuvochina et al. 2024</small>
- Class Brevinematia <small>Chuvochina et al. 2024</small>
- Brevinematales <small>Gupta et al. 2014</small>
- Class Brachyspiria <small>Chuvochina et al. 2024</small>
- Brachyspirales <small>corrig. Gupta et al. 2014</small>
- Class "Exilispiria" <small>Pallen, Rodriguez-R & Alikhan 2022</small>
- "Exilispirales" <small>Pallen, Rodriguez-R & Alikhan 2022</small>
- Class Spirochaetia <small>Paster 2020</small>
- ?Spirochaetales <small>Buchanan 1917</small>
- Borreliales <small>Chuvochina et al. 2024</small>
- Spirochaeta cellobiosiphila <small>Breznak & Warnecke 2008</small> {DSM-17781: DSM-17781}
- "Entomospirales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [WRBN01]
- "Candidatus Haliotispira" <small>Sharma et al. 2024</small> {SP-2023: SP-2023}
- "Marispirochaetales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [JC444]
- "Salinispirales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-27196]
- "Sediminispirochaetales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-16054]
- Sphaerochaetales <small>Chuvochina et al. 2024</small>
- Spirochaetales_E
- "Candidatus Thalassospirochaeta" <small>Pragya et al. 2024</small> {UBA9216: UBA9216}
- Treponematales <small>Chuvochina et al. 2024</small>
- "Winmispirales" <small>Podosokorskaya et al. 2025</small>
- "Candidatus Cellulosimonas" <small>Doud et al. 2020</small>
- Class "Ryujiniia" <small>Sun et al. 2025</small>
- "Ryujiniales" <small>Sun et al. 2025</small> [UBA6262]
- Class "Elusimicrobiia" <small>Oren, Parte & Garrity 2016 ex Cavalier-Smith 2020</small> (TG1)
- Elusimicrobiales <small>Geissinger et al. 2010</small>
- "Obscuribacteriales" <small>Uzun et al. 2023</small>
- Class "Endomicrobiia" <small>Stingl et al. 2018</small>
- "Endomicrobiales" <small>Zheng et al. 2018</small>
- Class "Aerophobia" <small>Chuvochina et al. 2023</small> (CD12)
- "Aerophobales" <small>Chuvochina et al. 2023</small>
- ?"Candidatus Neomarinimicrobium" <small>Rinke et al. 2013 corrig. Oren et al. 2020</small> (Candidate phylum SAR406; candidate phylum Marine Group A)
- Class Fidelibacteria <small>Katayama et al. 2024</small>
- Fidelibacterales <small>Katayama et al. 2024</small>
- Class "Heilongiia" <small>corrig. Zhang et al. 2022</small>
- ?"Heilongiales" <small>Zhang et al. 2022</small>
- Class "Saltatorellae" <small>Wiegand et al. 2019</small>
- ?"Saltatorellales" <small>Wiegand et al. 2019</small>
- Class "Hinthialibacteria" <small>Williams et al. 2022</small>
- "Hinthialibacterales" <small>Williams et al. 2022</small> (OLB16)
- Class "Sumerlaeia" <small>Kadnikov et al. 2018</small>
- "Sumerlaeales" <small>Kadnikov et al. 2018</small>
- Class "Hydrogenedentia" <small>Chuvochina et al. 2023</small> (NKB19)
- "Hydrogenedentales" <small>corrig. Chuvochina et al. 2023</small>
- Class "Ancaeobacteria" <small>Williams et al. 2022</small> [JAKLEM01]
- "Ancaeobacterales" <small>Williams et al. 2022</small>
- Class "Auribacteria" <small>Williams et al. 2022</small> [SURF-26]
- "Auribacterales" <small>Williams et al. 2022</small>
- Class "Erginobacteria" <small>Williams et al. 2022</small> [PUNC01]
- "Erginobacterales" <small>Williams et al. 2022</small>
- Class JACPWU01
- "Theseobacterales" <small>Williams et al. 2022</small>
- Class "Tritonobacteria" <small>Williams et al. 2022</small> [UBA1439]
- "Tritonobacterales" <small>Williams et al. 2022</small>
- Class Chlamydiia <small>Horn 2011</small>
- "Similichlamydiales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [Hat2]
- Chlamydiales <small>Storz & Page 1971 em. Everett et al. 1999</small> (Parachlamydiales, "Anoxychlamydiales", "Simkaniales")
- Class Lentisphaeria <small>Cho et al. 2004</small>
- Lentisphaerales <small>Cho et al. 2004</small>
- Oligosphaerales <small>Qiu et al. 2013</small>
- Victivallales <small>Cho et al. 2004</small>
- Class Kiritimatiellae <small>Spring et al. 2017</small>
- Kiritimatiellales <small>Spring et al. 2017</small> [incl. Tichowtungiales]
- "Spyradenecales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [RFP12]
- Class Verrucomicrobiia <small>corrig. Hedlund, Gosink & Staley 1998</small>
- Limisphaerales <small>Podosokorskaya et al. 2023</small>
- Methylacidiphilales <small>Awala et al. 2023</small> ["Pedosphaerales"]
- Opitutales <small>Choo et al. 2007</small> (Puniceicoccales)
- Terrimicrobiales <small>GarcÃÂa-López et al. 2020</small> ("Chthoniobacterales")
- Verrucomicrobiales <small>Ward-Rainey et al. 1996 em. Yoon et al. 2008</small>
- Class "Tangaroaeia" <small>Sun et al. 2025</small> ("Aegiribacteria")
- "Tangaroaeales" <small>Sun et al. 2025</small> (Hyd24-12)
- Class "Orphanbacteria" <small>Gong et al. 2022</small>
- "Orphanbacterales" <small>Gong et al. 2022</small>
- Class "Arandabacteria" <small>Gong et al. 2022</small>
- "Arandabacterales" <small>Gong et al. 2022</small>
- Class "Joyebacteria" <small>Gong et al. 2022</small>
- "Joyebacterales" <small>Gong et al. 2022</small>
- Class "Krumholzibacteriia" <small>corrig. Youssef et al. 2019</small>
- "Delphibacterales" (DOLZORAL124_64_63; LZORAL124-64-63)
- "Krumholzibacteriales" <small>Youssef et al. 2019</small> (UBP1)
- Class "Blakebacteria" <small>Gong et al. 2022</small>
- "Blakebacterales" <small>Gong et al. 2022</small>
- Class "Tepidihabitantia" <small>Slobodkina et al. 2025</small>
- ?"Tepidihabitantales" <small>Slobodkina et al. 2025</small> [UBA2258: JABLX01]
- Class "Stahliibacteriia" (UBA3073)
- Class "Hydrothermia" <small>Chuvochina et al. 2019 ex Chuvochina et al. 2023</small>
- "Hydrothermales" <small>Chuvochina et al. 2019 ex Chuvochina et al. 2023</small> (EM3)
- "Caldipriscales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [LBFQ01]
- Class "Cloacimonadia" <small>Williams et al. 2021 ex Chuvochina et al. 2023</small>
- "Candidatus Celaenobacter" Williams et al. 2021 {JGIOTU-2: JGIOTU-2}
- "Cloacimonadales" <small>Williams et al. 2021 ex Chuvochina et al. 2023</small> (WWE1)
- Class Calditrichia <small>Kublanov et al. 2022</small>
- Calditrichales <small>Kublanov et al. 2020</small>
- Family "Effluvivivacaceae" <small>corrig. Su et al. 2024</small> (VGIX01)
- Class "Kapaibacteriia" <small>corrig. Chuvochina et al. 2023</small> (OPB56)
- "Kapaibacteriales" <small>corrig. Chuvochina et al. 2023</small>
- Class "Kryptonia"
- "Kryptoniales"
- Class "Ignavibacteriia" <small>Oren, Parte & Garrity 2016 ex Cavalier-Smith 2022</small>
- Ignavibacteriales <small>Iino et al. 2010</small>
- "Tepidaquicellales" <small>corrig. Kadnikov et al. 2020</small>
- Class Chlorobiia <small>Oren, Parte & Garrity 2016 ex Cavalier-Smith 2020</small>
- Chlorobiales <small>Gibbons & Murray 1978</small>
- Class Rhodothermia <small>Munoz, Rossello-Mora & Amann 2017</small>
- Balneolales <small>Munoz, Rossello-Mora & Amann 2017</small>
- Rhodothermales <small>Munoz, Rossello-Mora & Amann 2017</small>
- Class "Electryoneia" <small>Williams et al. 2022</small>
- Electryoneales <small>Williams et al. 2022</small>
- Class AABM5-125-24
- Hatepunaeales <small>Williams et al. 2022</small>
- Class "Tariuqbacteria" <small>Vigneron, Vincent & Lovejoy 2023</small>
- Tariuqbacterales <small>Vigneron, Vincent & Lovejoy 2023</small>
- Class "Canglongiliia" <small>Zhang et al. 2022</small>
- ?"Canglongiales" <small>Zhang et al. 2022</small>
Phylum Desulfobacterota G
- Class Syntrophorhabdia <small>Waite et al. 2020</small>
- Syntrophorhabdales <small>Waite et al. 2020</small>
Phylum "Acidulodesulfobacteriota"
- Class "Acidulodesulfobacteriia" <small>(sic) Pallen, Rodriguez-R & Alikhan 2022</small> [SZUA-79]
- "Acidulidesulfobacterales" <small>corrig. Tan et al. 2019</small>
- Class "Dadabacteria" <small>(sic) Hug et al. 2016</small> [CSP1-2]
- "Nemesobacterales" <small>Gavriilidou et al. 2023</small>
- Class "Calescibacteriia" <small>Chuvochina et al. 2023</small> (EM19)
- "Calescibacteriales" <small>Chuvochina et al. 2023</small>
- Class Thermosulfidibacteria <small>Cavalier-Smith 2020 ex Chuvochina et al. 2024</small>
- Thermosulfidibacterales <small>Cavalier-Smith 2020 ex Chuvochina et al. 2024</small>
- Class Desulfurobacteriia <small>Chuvochina et al. 2024</small>
- Desulfurobacteriales <small>Gupta & Lali 2014</small>
- Class Aquificia <small>corrig. Reysenbach 2002</small>
- Aquificales <small>Reysenbach 2002</small> (Hydrogenothermales)
- Class "Deferrimicrobiia" <small>corrig. Begmatov et al. 2022</small>
- Deferrimicrobiales <small>Begmatov et al. 2022</small>
- Class "Lernaellia" <small>Williams et al. 2022</small> [FEN-1099]
- "Alcyoniellaceae" <small>Williams et al. 2022</small> {JAVCCG01}
- "Lernaellales" <small>Williams et al. 2022</small>
- Class "Binatia" <small>Chuvochina et al. 2019 ex Chuvochina et al. 2023</small>
- "Binatales" <small>Chuvochina et al. 2019 ex Chuvochina et al. 2023</small>
- Class "Kuafubacteriia" <small>corrig. Li et al. 2023</small>
- "Kuafubacteriales" <small>Li et al. 2023</small> [WYAZ01: GCA_016703535]
- Class Myxococcia <small>Waite et al. 2020</small>
- Myxococcales <small>Tchan, Pochon & Prévot 1948</small> [Archangiales; "Angiobacteriales"; "Angiococcales"] (fruiting gliding bacteria)
- Class Bradymonadia <small>corrig. Chuvochina et al. 2024</small>
- Bradymonadales <small>Wang et al. 2015</small>
- Class Polyangiia <small>corrig. Waite et al. 2020</small>
- Haliangiales <small>Waite et al. 2020</small>
- Nannocystales <small>(Reichenbach 2007) Waite et al. 2020 </small>
- Polyangiales <small>Tchan, Pochon & Prevot 1948</small> [Myxobacterales]
- Class "Moduliflexia" <small>Sekiguchi et al. 2015</small> (KSB3)
- "Moduliflexales" <small>Sekiguchi et al. 2015</small>
- Class "Spongiamicia" <small>Sun et al. 2025</small> [UBA8248]
- "Spongiamicales" <small>Sun et al. 2025</small>
- Class "Entotheonellia" <small>Chuvochina et al. 2023</small>
- "Entotheonellales" <small>Schmidt et al. 2000 ex Chuvochina et al. 2023</small>
- Class Nitrospinia <small>Lucker et al. 2022</small>
- Nitrospinales <small>Lucker et al. 2022</small>
- Class "Methylomirabilia" <small>Chuvochina et al. 2023</small>
- "Methylomirabilales" <small>Cabrol et al. 2020 ex Chuvochina et al. 2023</small>
- "Rokubacteriales" (CSP1-6)
- Class "Zymogeniia" <small>corrig. Murphy et al. 2021</small>
- "Zymogeniales" <small>Murphy et al. 2021</small>
- Class "Anaeroferrophilia" <small>corrig. Murphy et al. 2021</small>
- "Anaeroferrophilales" <small>Murphy et al. 2021</small> ["Tharpellales"]
- Class Desulfuromonadia <small>Waite et al. 2020</small>
- Desulfuromonadales <small>corrig. Kuever, Rainey & Widdel 2006</small>
- Geobacterales <small>Waite et al. 2020</small>
- Class Desulfomonilia <small>Waite et al. 2020</small>
- Desulfomonilales <small>Waite et al. 2020</small>
- Class Syntrophia <small>Waite et al. 2020</small>
- Syntrophales <small>Waite et al. 2020</small>
- Class Dissulfuribacteria <small>Waite et al. 2020</small>
- Dissulfuribacterales <small>Waite et al. 2020</small>
- Class Thermodesulfobacteriia <small>corrig. Hatchikian, Ollivier & Garcia 2002</small>
- Thermodesulfobacteriales <small>Hatchikian, Ollivier & Garcia 2002</small>
- Class Desulfobulbia <small>Waite et al. 2020</small>
- Desulfobulbales <small>Waite et al. 2020</small>
- Class "Desulfofervidia" <small>Waite et al. 2020</small>
- "Desulfofervidales" <small>Waite et al. 2020</small>
- Class "Desulfatiglandia" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-4660]
- Desulfatiglandales <small>Waite et al. 2020</small>
- Class Desulfobaccia <small>Waite et al. 2020</small>
- Desulfobaccales <small>Waite et al. 2020</small>
- Class Desulfarculia <small>Waite et al. 2020</small>
- "Adiutricales" <small>Waite et al. 2020</small>
- Desulfarculales <small>corrig. Kuever, Rainey & Widdel 2006</small>
- Class Syntrophobacteria <small>Waite et al. 2020</small>
- Syntrophobacterales <small>Waite et al. 2020</small>
- Class Desulfobacteria <small>Waite et al. 2020</small>
- Desulfobacterales <small>Kuever, Rainey & Widdel 2006</small>
- Class "Leptospirillia" <small>Chuvochina et al. 2023</small>
- "Leptospirillales" <small>Chuvochina et al. 2023</small>
Phylum SAR324
- Class "Anaeropigmentatia" <small>corrig. Murphy et al. 2021</small>
- ?Anaeropigmentatales <small>corrig. Murphy et al. 2021</small>
- Class Caulobacteria" <small>Oren, Parte & Garrity 2016 ex Cavalier-Smith 2020</small>
- ?"Methylospongiales" <small>Podell et al. 2020</small>
- Clade "Rhodobacteriae"
- Hyphomicrobiales <small>Douglas 1957</small> (Rhizobiales)
- "Pelagibacterales" <small>Grote et al. 2012</small>
- Rhodobacterales <small>Garrity, Bell & Lilburn 2006</small>
- Sublass "Rickettsiidae" <small>corrig. Ferla et al. 2013</small>
- "Enterousiales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> {Rs-D84}
- Rickettsiales <small>Gieszczykiewicz 1939 emend. Dumler et al. 2001</small>
- "Scatocolales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [RF32]
- Subclass "Pseudomonadidae" <small>Cavalier-Smith 2020</small>
- "Ca. Legionella polyplacis" <small>RÃÂhová et al. 2017</small> {G002776555: G002776555}
- Acidiferrobacterales <small>Kojima, Shinohara & Fukui 2015</small>
- Acidihalobacteraceae Chuvochina et al. 2024 {DSM-5130}
- "Aquicellales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-16500]
- Arenicellales <small>Teramoto, Yagyu & Nishijima 2015</small>
- "Azoamicaceae" <small>Speth et al. 2023</small> {G016432505}
- Beggiatoales <small>Buchanan 1957</small>
- "Berkiellales" <small>Chuvochina et al. 2023</small>
- Cardiobacteriales <small>Garrity, Bell & Lilburn 2005</small>
- Chromatiales <small>Imhoff 2005</small>
- "Comchoanobacterales" <small>Needham et al. 2022</small>
- "Competibacterales" <small>Chuvochina et al. 2023</small>
- Coxiellales <small>Chuvochina et al. 2024</small>
- Diplorickettsiales <small>Chuvochina et al. 2024</small>
- Ectothiorhodospirales <small>Chuvochina et al. 2024</small>
- Enterobacterales <small>Adeolu et al. 2016</small> ("Bacteriales"; Orbales; "Aerobacterales"; Aeromonadales; Alteromonadales; Kangiellales; Pasteurellales; "Vibrionales")
- Enterobacteriaceae_A {Enterobacterales_A}
- "Foliamicales" <small>Nguyen et al. 2023</small>
- Francisellales <small>Chuvochina et al. 2024</small>
- Granulosicoccales <small>Chuvochina et al. 2024</small>
- "Halofilales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [XJ16]
- Halothiobacillales <small>Chuvochina et al. 2024</small>
- Immundisolibacterales <small>Corteselli, Aitken & Singleton 2017</small>
- "Inmiraniales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-100275]
- Legionellales <small>Garrity, Bell & Lilburn 2005</small>
- "Macondimonadales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [UBA5335]
- "Magnimaribacterales" Ramfelt et al. 2024 [SAR86: SAR156]
- Methylococcales <small>Bowman 2005</small>
- Methylohalomonadales <small>Sorokin & Merkel 2023</small> ("Eutrophobiales")
- Natronospirales <small>Sorokin et al. 2025</small>
- Nevskiales <small>Naushad et al. 2015</small> ("Salinisphaerales")
- Nitrococcales <small>Chuvochina et al. 2024</small>
- Nitrosococcales <small>Chuvochina et al. 2024</small>
- "Pelagibaculales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [HP12]
- Piscirickettsiales <small>Chuvochina et al. 2024</small>
- "Porifericomitales" <small>Nguyen et al. 2023</small>
- "Poriferisulfidales" <small>Nguyen et al. 2023 ex Chuvochina et al. 2023</small>
- Pseudomonadales <small>Orla-Jensen 1921</small> (Cellvibrionales; Moraxellales; Oceanospirillales)
- "Rariloculales" <small>Nguyen et al. 2022</small>
- "Reidiellales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [GCF-013343005]
- Steroidobacterales <small>Chuvochina et al. 2024</small>
- "Sulfuriflexales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [AKS1]
- "Taraoceanobacteraceae" <small>Zhou et al. 2020</small> {UBA11654}
- "Tenderiales" <small>Chuvochina et al. 2023</small>
- "Thioalbales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-26407]
- "Thioglobales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [PS1]
- "Thiogranales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-19610]
- Thiohalobacterales <small>Sorokin & Merkel 2023</small>
- Thiohalomonadales <small>Sorokin & Merkel 2023</small>
- "Thiohalophilales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> {UBA6429}
- Thiohalospirales <small>Sorokin & Merkel 2023</small>
- Thiomicrospirales <small>Chuvochina et al. 2024</small>
- "Thiopontiales" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [GCF-002020875]
- Thiotrichales <small>Garrity, Bell & Lilburn 2005</small>
- Woeseiales <small>Chuvochina et al. 2024</small>
- Xanthomonadales <small>Saddler & Bradbury 2005 non Chadefaud 1950a</small> (Lysobacterales)
List of Candidate Phyla
See also
References