List of Archaea genera


This article lists the genera of the Archaea and also shows taxa of archaea that do not contain genera. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature and National Center for Biotechnology Information unless otherwise noted.

Phylogeny

For the GTDB phylogeny, National Center for Biotechnology Information 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 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 the GTDB release 10-RS226.

Phylum [Microcaldota]

Class Microcaldia

Order Microcaldales

Phylum "[Altarchaeota]"

Class "Altarchaeia"

Order "Altarchaeales"

  • Family "Altarchaeaceae" corrig. Probst et al. 2014
  • * "Candidatus Altarchaeum" corrig. Probst et al. 2014

Phylum "[Iainarchaeota]"

Class "Iainarchaeia"

Order "Forterreales"

  • Family "Forterreaceae" Pallen, Rodriguez-R & Alikhan 2022
  • * "Candidatus Forterrea" Probst & Banfield 2017

Order "Iainarchaeales"

  • Family "Iainarchaeaceae" Rinke et al. 2020
  • * "Candidatus Iainarchaeum" Rinke et al. 2013

Phylum "[Micrarchaeota]"

Class "Micrarchaeia"

Order "Norongarragalinales"

  • Family "Norongarragalinaceae" Vázquez-Campos et al. 2021
  • * "Candidatus Norongarragalina" Vázquez-Campos et al. 2021

Order "Micrarchaeales"

  • Family "Micrarchaeaceae" Vázquez-Campos et al. 2021
  • * "Candidatus Mancarchaeum" Golyshina et al. 2017
  • * "Candidatus Micrarchaeum" Baker et al. 2010

Order "Anstonellales"

  • Family "Anstonellaceae" Vázquez-Campos et al. 2021
  • * "Candidatus Anstonella" Vázquez-Campos et al. 2021
  • Family "Bilamarchaeaceae" Vázquez-Campos et al. 2021
  • * "Candidatus Bilamarchaeum" Vázquez-Campos et al. 2021

Order "Gugararchaeales"

  • Family "Gugararchaeaceae" Vázquez-Campos et al. 2021
  • * "Candidatus Gugararchaeum" Vázquez-Campos et al. 2021

Order "Burarchaeales"

  • Family "Burarchaeaceae" Vázquez-Campos et al. 2021
  • * "Candidatus Burarchaeum" Vázquez-Campos et al. 2021

Order "Fermentimicrarchaeales"

  • Family "Fermentimicrarchaeaceae" Kadnikov et al. 2020
  • * "Candidatus Fermentimicrarchaeum" Kadnikov et al. 2020

Phylum "[Undinarchaeota]"

Class "Undinarchaeia"

Order "Undinarchaeales"

  • Family "Naiadarchaeaceae" Dombrowski et al. 2020
  • * "Candidatus Naiadarchaeum" Dombrowski et al. 2020
  • Family "Undinarchaeaceae" Dombrowski et al. 2020
  • * "Candidatus Undinarchaeum" Dombrowski et al. 2020

Phylum "[Huberarchaeaota]"

Class "Huberarchaeia"

Order "Huberarchaeales"

  • Family "Huberarchaeaceae" Rinke et al. 2020
  • * "Candidatus Huberarchaeum" corrig. Schwank et al. 2019

Phylum "Aenigmatarchaeota">Aenigmarchaeota">Aenigmatarchaeota"

Class "Aenigmatarchaeia"

Order "Aenigmatarchaeales"

  • Family "Aenigmatarchaeaceae" corrig. Rinke et al. 2020
  • * "Candidatus Aenigmatarchaeum" corrig. Rinke et al. 2013

Phylum "Nanohalarchaeota">Nanohaloarchaeota">Nanohalarchaeota"

Class "Nanohalarchaeia"

Order "Nanohalarchaeales"

  • Family "Nanohalarchaeaceae"
  • * ?"Candidatus Nanohalarchaeum" corrig. Hamm et al. 2019
  • * ?"Candidatus Nanopetraeus" corrig. Crits‐Christoph et al. 2016

Order "Nanohydrothermales"

  • Family "Nanohydrothermaceae" Xie et al. 2022
  • * ?"Candidatus Nanohydrothermus" Xie et al. 2022

Order "Nucleotidisoterales"

  • Family "Nanosalenecaceae" Xie et al. 2022
  • * ?"Candidatus Nanosalenecus" Xie et al. 2022
  • Family "Nucleotidisoteraceae" Xie et al. 2022
  • * ?"Candidatus Nucleotidisoter" Xie et al. 2022
  • Family "Nucleotidivindicaceae" Xie et al. 2022
  • * ?"Nucleotidivindex" Xie et al. 2022

Class "Nanohalobiia"

Order "Nanohalobiales"

  • Family "Nanoanaerosalinaceae" Zhao et al. 2022
  • * "Candidatus Asbonarchaeum" Baker et al. 2024
  • * "Candidatus Nanoanaerosalina" Zhao et al. 2022
  • Family "Nanohalalkaliarchaeaceae" La Cono et al. 2020
  • * "Candidatus Nanohalalkaliarchaeum" Ghai et al. 2011
  • Family "Nanohalobiaceae" La Cono et al. 2020
  • * ?"Candidatus Haloredivivus" Ghai et al. 2011
  • * "Candidatus Nanohalobium" La Cono et al. 2020
  • * "Candidatus Nanohalococcus" Reva et al. 2023
  • * "Candidatus Nanosalina" Narasingarao et al. 2012
  • * "Candidatus Nanosalinicola" corrig. Narasingarao et al. 2012
  • * "Candidatus Nanohalovita" Reva et al. 2023

Phylum Nanobdellota">Nanoarchaeota">Nanobdellota

Class Nanobdellia

Order "Pacearchaeales"
'''Order "Woesearchaeales"'''

Order Nanobdellales

  • Family "Nanoarchaeaceae" Huber et al. 2011
  • * "Nanoarchaeum" Huber et al. 2002
  • Family Nanobdellaceae Kato et al. 2022
  • * Nanobdella Kato et al. 2022
  • * "Candidatus Nanoclepta" St. John et al. 2019

Order "Tiddalikarchaeales"

  • Family "Tiddalikarchaeaceae" Vázquez-Campos et al. 2021
  • * "Candidatus Tiddalikarchaeum" Vázquez-Campos et al. 2021

Order "Jingweiarchaeales"

  • Family "Jingweiarchaeaceae" Rao et al. 2023
  • * "Candidatus Jingweiarchaeum" Rao et al. 2023

Order JAPDLS01

  • Family "Haiyanarchaeaceae" Rao et al. 2023
  • * "Candidatus Haiyanarchaeum" Rao et al. 2023

Order "Parvarchaeales"

  • Family "Parvarchaeaceae" Rinke et al. 2020
  • * "Candidatus Acidifodinimicrobium" Luo et al. 2020
  • * "Candidatus Parvarchaeum" Baker et al. 2010
  • * "Candidatus Rehaiarchaeum" Rao et al. 2023

Phylum Promethearchaeota

Taxonomy of this group is based on LPSN, and also these works:

Promethearchaeota incertae sedis

  • ?"Friggarchaeota" Caceres 2019
  • ?"Gefionarchaeota" Caceres 2019
  • ?"Idunnarchaeota" Caceres 2019
  • ?"Sleipnirarchaeota" Kioukis et al. 2025
  • ?"Candidatus Balderarchaeum" Xie et al. 2022
  • ?"Candidatus Sukunaarchaeum" Harada et al. 2025
  • ?"Candidatus Tyrarchaeum" Xie et al. 2022

Class "Asgardarchaeia"

Order "Asgardarchaeales"

  • Family "Asgardarchaeaceae" Eme et al. 2023 ex Tamarit et al. 2024
  • * "Candidatus Asgardarchaeum" Eme et al. 2023 ex Tamarit et al. 2024

Class "Atabeyarchaeia"

Order "Atabeyarchaeales"

  • Family "Atabeyarchaeaceae" Valentin-Alvaradoet al. 2024
  • * "Candidatus Atabeyarchaeum" Valentin-Alvarado et al. 2024

Class "Sifarchaeia"

Order "Sifarchaeales"

  • Family "Sifarchaeaceae" Sun et al. 2021
  • * "Candidatus Sifarchaeum" corrig. Farag, Zhao & Biddle 2020

Order "Borrarchaeales"

  • Family "Borrarchaeaceae" Liu et al. 2021
  • * "Candidatus Borrarchaeum" Liu et al. 2021

Class "Wukongarchaeia"

Order "Wukongarchaeales"

  • Family "Wukongarchaeaceae" Liu et al. 2021
  • * "Candidatus Wukongarchaeum" Liu et al. 2021

Class "Njordarchaeia"

Order "Njordarchaeales"

  • Family "Panguiarchaeaceae" Qu et al. 2023
  • * "Panguiarchaeum" Qu et al. 2023
  • Family "Njordarchaeaceae" Xie et al. 2022
  • * "Candidatus Njordarchaeum" Xie et al. 2022

Class "Heimdallarchaeia"

Order "Hodarchaeales"

  • Family "Hodarchaeaceae" Liu et al. 2021
  • * "Candidatus Hodarchaeum" Liu et al. 2021
  • Family "Margulisarchaeaceae" Imachi et al. 2025
  • * ?"Candidatus Flexarchaeum" Imachi et al. 2025
  • * ?"Candidatus Margulisarchaeum" Imachi et al. 2025

Order "Heimdallarchaeales"

  • Family "Kariarchaeaceae" Liu et al. 2021
  • * "Candidatus Kariarchaeum" Liu et al. 2021
  • Family "Heimdallarchaeaceae" Wu et al. 2022
  • * "Candidatus Heimdallarchaeum" Wu et al. 2022

Class "Odinarchaeia"

Order "Odinarchaeales"

  • Family "Odinarchaeaceae" Tamarit et al. 2022
  • * "Candidatus Odinarchaeum" Tamarit et al. 2022

Class "Jordarchaeia"

Order "Jordarchaeales"

  • Family "Freyrarchaeaceae" Xie et al. 2022
  • * "Candidatus Freyrarchaeum" Xie et al. 2022
  • Family "Jordarchaeaceae" Sun et al. 2021
  • * "Candidatus Jordarchaeum" Sun et al. 2021

Class "Baldrarchaeia"

Order "Baldrarchaeales"

  • Family "Baldrarchaeaceae" corrig. Liu et al. 2021
  • * "Candidatus Baldrarchaeum" Liu et al. 2021

Class "[Thorarchaeia]"

Order "Thorarchaeales"

  • Family "Thorarchaeaceae"

Class "Hermodarchaeia"

Order "Hermodarchaeales"

  • Family "Hermodarchaeaceae" corrig. Liu et al. 2021
  • * "Candidatus Hermodarchaeum" Liu et al. 2021

Class Promethearchaeia">Lokiarchaeia">Promethearchaeia

Order Promethearchaeales">Promethearchaeaceae">Promethearchaeales

  • Family Sigynarchaeaceae Xie et al. 2022
  • * "Candidatus Sigynarchaeum" Xie et al. 2022
  • Family Promethearchaeaceae Imachi et al. 2024
  • * "Candidatus Harpocratesius" Wu et al. 2022
  • * "Candidatus Lokiarchaeum" corrig. Spang et al. 2015
  • * Promethearchaeum Imachi et al. 2024

Phylum "[Korarchaeota]"

Class "Korarchaeia"

Order "Korarchaeales"

  • Family "Korarchaeaceae" Rinke et al. 2020
  • * "Candidatus Korarchaeum" Elkins et al. 2008
  • * "Candidatus Methanodesulfokora" McKay et al. 2019

Phylum [Thermoproteota]

Class "[Bathyarchaeia]"

Order "Bifangarchaeales"

  • Family "Bifangicolaceae" Hou et al. 2023
  • * ?"Candidatus Bifangicola" Hou et al. 2023
  • Family "Bifangarchaeaceae" Hou et al. 2023
  • * "Candidatus Bifangarchaeum" corrig. Hou et al. 2023
  • Family "Bifangistellaceae" Hou et al. 2023
  • * "Candidatus Bifangistella" Hou et al. 2023

Order "Xuanwuarculales"

  • Family "Mazuisomaceae" Hou et al. 2023
  • * ?"Candidatus Mazuisoma" Hou et al. 2023
  • Family "Mazuicellaceae" Hou et al. 2023
  • * ?"Candidatus Mazuibellus" Hou et al. 2023
  • * ?"Candidatus Mazuicella" Hou et al. 2023
  • Family "Mazuousiaecae" Hou et al. 2023
  • * ?"Candidatus Mazuarcula" Hou et al. 2023
  • * ?"Candidatus Mazuousia" Hou et al. 2023
  • Family "Xuanwuarculaceae" Hou et al. 2023
  • * "Candidatus Xuanwuarcula" Hou et al. 2023

Order "Hecatellales"

  • Family "Hecatellaceae" Rinke et al. 2020
  • * "Candidatus Hecatella" Adam et al. 2022
  • * "Candidatus Jinwuarcula" Hou et al. 2023
  • * "Candidatus Jinwuicola" Hou et al. 2023
  • * ?"Candidatus Jinwuimonas" Hou et al. 2023
  • * "Candidatus Jinwuimorpha" Hou et al. 2023
  • * ?"Candidatus Jinwuiprofundus" Hou et al. 2023
  • * ?"Candidatus Jinwuousia" Hou et al. 2023

Order "Houtuarculales"

  • Family "Houtuithermaceae" Hou et al. 2023
  • * ?"Candidatus Houtuithermus" Hou et al. 2023
  • Family "Marihoutuimonadaceae" Hou et al. 2023
  • * ?"Candidatus Houtuibellus" Hou et al. 2023
  • * ?"Candidatus Marihoutuimonas" Hou et al. 2023
  • Family "Crenohoutuithermaceae" Hou et al. 2023
  • * "Candidatus Crenohoutuithermus" Hou et al. 2023
  • Family "Fontihoutuithermaceae" Hou et al. 2023
  • * ?"Candidatus Fluxihoutuithermus" Hou et al. 2023
  • * "Candidatus Fontihoutuithermus" Hou et al. 2023
  • Family "Aphrohoutuibellaceae" Hou et al. 2023
  • * "Candidatus Aphrohoutuibellus" Hou et al. 2023
  • * "Candidatus Hydrohoutuibellus" Hou et al. 2023
  • Family "Houtuousiaceae" Hou et al. 2023
  • * "Candidatus Houtuousia" Hou et al. 2023
  • Family "Houtuarculaceae" Hou et al. 2023
  • * ?"Candidatus Limnohoutuiplasma" Hou et al. 2023
  • * "Candidatus Houtuarcula" Hou et al. 2023

Order "Wuzhiqiibiales"

  • Family "Wuzhiqiithermaceae" Hou et al. 2023
  • * ?"Candidatus Wuzhiqiithermus" Hou et al. 2023
  • Family "Wuzhiqiitorraceae" Hou et al. 2023
  • * ?"Candidatus Wuzhiqiitorris" Hou et al. 2023
  • Family "Wuzhiqiimorphaceae" Hou et al. 2023
  • * "Candidatus Wuzhiqiimorpha" Hou et al. 2023
  • Family "Wuzhiqiimonadaceae" Hou et al. 2023
  • * "Candidatus Wuzhiqiimonas" Hou et al. 2023
  • Family "Wuzhiqiibiaceae" Hou et al. 2023
  • * "Candidatus Wuzhiqiibium" Hou et al. 2023

Order "Zhuquarculales"

  • Family "Zhuquarculaceae" Hou et al. 2023
  • * "Candidatus Zhuquarcula" Hou et al. 2023
  • Family "Zhuquomorphaceae" Hou et al. 2023
  • * "Candidatus Zhuquomorpha" Hou et al. 2023

Order "Bathyarchaeales"

  • Family "Actozhurongousiaceae" Hou et al. 2023
  • * ?"Candidatus Actozhurongousia" Hou et al. 2023
  • Family "Yuguousiaceae" Hou et al. 2023
  • * ?"Candidatus Yuguousia" Hou et al. 2023
  • Family "Pontizhurongicolaceae" Hou et al. 2023
  • * "Candidatus Pontizhurongicola" Hou et al. 2023
  • Family "Hanbarchaeaceae" Hou et al. 2023
  • * "Candidatus Fufeiimorpha" Hou et al. 2023
  • * "Candidatus Hanbarchaeum" Hou et al. 2023
  • * "Candidatus Zhurongicella]" Hou et al. 2023
  • Family "Marizhurongicellaceae" Hou et al. 2023
  • * ?"Candidatus Aoguangisoma" Hou et al. 2023
  • * "Candidatus Marizhurongibium" Hou et al. 2023
  • * "Candidatus Marizhurongicella" Hou et al. 2023
  • * ?"Candidatus Yanziimonas" Hou et al. 2023
  • * ?"Candidatus Zhurongibium" Hou et al. 2023
  • Family "Hanbopyraceae" Hou et al. 2023
  • * "Candidatus Hanbopyrus" Hou et al. 2023
  • Family "Jingweiiplasmataceae" Hou et al. 2023
  • * "Candidatus Jingweiiplasma" Hou et al. 2023
  • Family "Bathyarchaeaceae" Khomyakova et al. 2023
  • * "Candidatus Baizobellus" Hou et al. 2023
  • * ?"Candidatus Baizosediminiarchaeum" Yu et al. 2023
  • * "Candidatus Baizosoma" Hou et al. 2023
  • * ?"Candidatus Baizostella" Hou et al. 2023
  • * "Candidatus Bathyarchaeum" Khomyakova et al. 2023
  • * "Candidatus Halozhurongicella" Hou et al. 2023
  • Family "Bathycorpusculaceae" Loh & Brune 2023
  • * ?"Candidatus Aoshunithermus" Hou et al. 2023
  • * ?"Candidatus Baizomonas" Hou et al. 2023
  • * "Candidatus Baizomorpha" Hou et al. 2023
  • * "Candidatus Bathycorpusculum" Loh & Brune 2023
  • * "Candidatus Buyanhuyuicella" Hou et al. 2023
  • * "Candidatus Buyanhuyuitorris" Hou et al. 2023
  • * "Candidatus Hanbocola" Hou et al. 2023
  • * "Candidatus Hanbothermus" Hou et al. 2023
  • * "Candidatus Yanziithermus" Hou et al. 2023
  • * "Candidatus Yuguotorris" Hou et al. 2023

Class Nitrososphaeria_A">Nitrososphaerota">Nitrososphaeria_A

Order "Caldarchaeales"

  • Family "Calditenuaceae" Balbay et al. 2023
  • * "Candidatus Calditenuis" Beam et al. 2016
  • Family "Caldarchaeaceae" Rinke et al. 2020
  • * "Candidatus Caldarchaeum" corrig. Nunoura et al. 2011
  • * "Candidatus Pelearchaeum" Balbay et al. 2023
  • Family "Wolframiiraptoraceae" Buessecker et al. 2022
  • * "Candidatus Benthortus" Buessecker et al. 2022
  • * "Candidatus Geocrenenecus" Buessecker et al. 2022
  • * "Candidatus Terraquivivens" Buessecker et al. 2022
  • * "Candidatus Wolframiiraptor" Buessecker et al. 2022

Class Nitrososphaeria">Nitrososphaerota">Nitrososphaeria

Nitrososphaeria incertae sedis

  • ?"Candidatus Cenoporarchaeum" corrig. Zhang et al. 2019
  • ?"Candidatus Gigantothauma" corrig. Muller et al. 2010
  • ?"Candidatus Nitrosodeserticola" Hwang et al. 2021

Order "Geothermarchaeales"

  • Family "Geothermarchaeaceae" Adam et al. 2022
  • * "Candidatus Geothermarchaeum" Adam et al. 2022
  • * "Candidatus Scotarchaeum" Adam et al. 2022

Order PSMU01

  • Family PSMU01
  • * "Candidatus Australarchaeum" Herbold et al. 2024

Order "Conexivisphaerales"

  • Family "Conexivisphaeraceae" Kato et al. 2021
  • * Conexivisphaera Kato et al. 2021

Order [Nitrososphaerales]

  • Family "Methylarchaceae" Hua et al. 2019
  • * ?"Candidatus Methylarchaeum" Hua et al. 2019
  • * ?"Candidatus Methanotowutia" Ou et al. 2022
  • Family "Gagatemarchaeaceae" Sheridan et al. 2023
  • * "Candidatus Gagatemarchaeum" Sheridan et al. 2023
  • * ?"Candidatus Subgagatemarchaeum" Sheridan et al. 2023
  • Family "Nitrosocaldaceae" Qin et al. 2016
  • * "Candidatus Nitrosocaldus" de la Torre et al. 2008
  • * "Candidatus Nitrosothermus" Luo et al. 2021
  • Family "Nitrosomiraceae" Zheng et al. 2024
  • * "Candidatus Nitrosomirus" Zheng et al. 2024
  • Family Nitrososphaeraceae Stieglmeier et al. 2014
  • * "Candidatus Nitrosocosmicus" corrig. Lehtovirta-Morley et al. 2016
  • * "Candidatus Nitrosopolaris" Pessi, Rutanen & Hultman 2022
  • * Nitrososphaera Stieglmeier et al. 2014
  • Family Nitrosopumilaceae Qin et al. 2017
  • * "Cenarchaeum" DeLong & Preston 1996
  • * Nitrosarchaeum corrig. Jung et al. 2018
  • * "Candidatus Nitrosoabyssus" Garritano et al. 2024
  • * ?"Candidatus Nitrosokoinonia" Glasl et al. 2023
  • * "Candidatus Nitrosomaritimum" Zhao et al. 2024
  • * "Candidatus Nitrosopelagicus" Santoro et al. 2015
  • * Nitrosopumilus Qin et al. 2017
  • * ?"Candidatus Nitrosospongia" Moeller et al. 2019
  • * "Candidatus Nitrosotalea" Lehtovirta 2011
  • * "Candidatus Nitrosotenuis" Lebedeva et al. 2013

Class "Methanomethylicia"

Order "Methanohydrogenicales"
  • * Family "Methanohydrogenicaceae" Berghuis et al. 2019
  • ** ?"Candidatus Methanohydrogenicus" Berghuis et al. 2019Order "Methanomethylarchaeales"
  • * Family "Methanomethylarchaeceae" corrig. Hua et al. 2019
  • ** ?"Candidatus Methanomethylarchaeum" corrig. Hua et al. 2019Order "Methanomethylovorales"
  • * Family "Methanomethylovoraceae" Hua et al. 2019
  • ** ?"Candidatus Methanomethylovorus" Hua et al. 2019

Order "Nezhaarchaeales"

  • Family "Methanohydrogenotrophicaceae" Hua et al. 2019
  • * ?"Candidatus Methanogearchaeum" corrig. Hua et al. 2019
  • * ?"Candidatus Methanohydrogenotrophicum" Hua et al. 2019

Order "Culexarchaeles"

  • Family "Culexarchaeaceae" Kohtz et al. 2022
  • * "Candidatus Culexarchaeum" Kohtz et al. 2022
  • Family "Culexmicrobiaceae" Kohtz et al. 2022
  • * "Candidatus Culexmicrobium" Kohtz et al. 2022

Order "Methanosuratincolales"

  • Family "Candidatus Methanosuratincolaceae" Wu et al. 2025
  • * ?"Candidatus Methanoluiimicrobium" Wu et al. 2024
  • * "Candidatus Methanomethylicus" Vanwonterghem et al. 2016
  • * ?"Candidatus Methanostamsia" Wu et al. 2024
  • * "Candidatus Methanosuratinicola" corrig. Vanwonterghem et al. 2016

Class [Thermoprotei]a

Order "Gearchaeales"

  • Family "Gearchaeaceae" corrig.
  • * ?Geoarchaeum Hunt et al. 2016

Order Thermofilales

Order [Thermoproteales]

Class "Sulfolobia"

Order "Tardisphaerales"

  • Family "Marsarchaeaceae"
  • Family "Tardisphaerace" Prokofeva et al. 2025
  • * ?"Tardisphaera" Prokofeva et al. 2025

Order [Sulfolobales]

Phylum "[Hadarchaeota]"

Class "Hadarchaeia"

Order "Hadarchaeales"

  • Family "Cerberiarchaeaceae" Benito Merino et al. 2024
  • * ?"Candidatus Cerberiarchaeum" Benito Merino et al. 2024
  • * ?"Candidatus Melinoarchaeum" Yu et al. 2024
  • Family "Hadarchaeaceae" Chuvochina et al. 2019 ex Chuvochina et al. 2023
  • * "Candidatus Hadarchaeum" Chuvochina et al. 2019
  • * ?"Candidatus Hadesarchaeum" Hua et al. 2019
  • * ?"Candidatus Methanourarchaeum" Hua et al. 2019

Phylum Methanobacteriota_B

Class [Thermococci]

Order "Methanofastidiosales"

  • Family "Methanofastidiosaceae" Rinke et al. 2020
  • * "Candidatus Methanofastidiosum" Nobu et al. 2016

Order [Thermococcales]

Phylum "[Hydrothermarchaeota]"

Class "Hydrothermarchaeia"

Order "Hydrothermarchaeales"

  • Family BMS3B
  • * "Candidatus Pyrohabitans" Adam et al. 2022
  • Family "Hydrothermarchaeaceae" Chuvochina et al. 2019
  • * "Candidatus Hydrothermarchaeum" Chuvochina et al. 2019

Phylum [Methanobacteriota]

Class "[Methanococci]a"

Order [Methanococcales]

Class [Methanopyri]a

Order [Methanopyrales]

Class Methanobacteriia">Methanobacteria">Methanobacteriia

Order [Methanobacteriales]

  • Family Methanothermaceae Stetter et al. 1982
  • * Methanothermus Stetter et al. 1982
  • Family Methanothermobacteraceae Chuvochina et al. 2024
  • * Methanothermobacter Wasserfallen et al. 2000
  • Family Methanobacteriaceae Barker 1956
  • * "Methanacia" Protasov & Brune 2023
  • * "Methanarmilla" Protasov & Brune 2023
  • * Methanobacterium Kluyver & van Niel 1936
  • * "Methanobaculum" Protasov & Brune 2023
  • * "Methanobinarius" Protasov & Brune 2023
  • * Methanobrevibacter Balch & Wolfe 1981
  • * "Methanocatella" Protasov & Brune 2023
  • * "Methanoflexus" Protasov & Brune 2023
  • * "Methanorudis" Protasov & Brune 2023
  • * Methanosphaera Miller & Wolin 1985
  • * "Methanovirga" Protasov & Brune 2023

Phylum [Thermoplasmatota]

Class "Izemarchaea"

Order "[Thermoprofundales]"

*

Class "Poseidoniia"

Order "Poseidoniales"

  • Family "Poseidoniaceae" Rinke et al. 2019
  • * "Candidatus Poseidonia" Rinke et al. 2019
  • Family "Thalassarchaeaceae" Rinke et al. 2019
  • * "Candidatus Thalassarchaeum" corrig. Martin-Cuadrado et al. 2015

Class "Penumbrarchaeia"

Order "Penumbrarchaeales"

  • Family "Penumbrarchaeaceae" Maeke et al. 2025
  • * "Candidatus Penumbrarchaeum" Maeke et al. 2025

Class [Thermoplasmata]

Order "Lunaplasmatales"

  • Family "Lunaplasmataceae" corrig. Zinke et al. 2021
  • * ?"Candidatus Lunaplasma" Zinke et al. 2021

Order "Proteinoplasmatales"

*

Order "[Yaplasmatales]"

Order "Gimiplasmatales"

  • Family "Gimiplasmataceae" Hu et al. 2020
  • * "Candidatus Gimiplasma" Hu et al. 2020

Order "Sysuiplasmatales"

  • Family "Sysuiplasmataceae" Yuan et al. 2021
  • * "Candidatus Sysuiplasma" Yuan et al. 2021

Order [Methanomassiliicoccales]

  • Family "Methanomixtatrophicaceae" Hua et al. 2019
  • * ?"Candidatus Methanomixtatrophicum" Hua et al. 2019
  • Family Methanomassiliicoccaceae Iino et al. 2013
  • * Methanomassiliicoccus Dridi et al. 2012
  • Family Methanomethylophilaceae Gaci et al. 2014 ex Borrel et al. 2024
  • * "Methanarcanum" Chibani et al. 2023
  • * "Methanogranum" Iino et al. 2023
  • * Methanomethylophilus Borrel et al. 2024
  • * "Candidatus Methanomicula" Protasov & Brune 2023
  • * "Methanoplasma" Lang & Brune 2023
  • * "Methanoprimaticola" Chibani et al. 2023
  • * ?"Candidatus Methanospyradousia" Gilroy et al. 2021

Order "Halarchaeoplasmatales"

  • Family "Halarchaeoplasmataceae" Zhou et al. 2023
  • * "Candidatus Haladaptiplasma" corrig. Zhou et al. 2022
  • * "Candidatus Halarchaeoplasma" Zhou et al. 2023
  • * "Candidatus Natronoplasma" Zhou et al. 2022
  • * "Candidatus Saliniplasma" Zhou et al. 2022

Order "Lutacidiplasmatales"

  • Family "Lutacidiplasmataceae" Sheridan et al. 2022
  • * "Candidatus Lutacidiplasma" Sheridan et al. 2022

Order "Aciduliprofundales"

  • Family "Aciduliprofundaceae" Rinke et al. 2020
  • * "Aciduliprofundum" Reysenbach et al. 2006

Order [Thermoplasmatales]

  • Family Thermoplasmataceae Reysenbach 2002
  • * Acidiplasma Golyshina et al. 2009
  • * ?"Candidatus Carboxiplasma" Bulaev et al. 2023
  • * Cuniculiplasma corrig. Golyshina et al. 2016
  • * Ferroplasma Golyshina et al. 2000
  • * ?Oxyplasma Golyshina et al. 2024
  • * Picrophilus Schleper et al. 1996
  • * ?"Candidatus Scheffleriplasma" Krause et al. 2022
  • * Thermogymnomonas Itoh, Yoshikawa & Takashina 2007
  • * Thermoplasma Darland et al. 1970

Phylum [Halobacteriota]

Halobacteriota incertae sedis

  • ?"Candidatus Methanoinsularis" Ou et al. 2022
  • ?"Candidatus Methanoporticola" Ou et al. 2022
  • Order "Methanoflorentales"
  • * Family "Methanoflorentaceae" Mondav et al. 2014
  • ** ?"Candidatus Methanoflorens" Mondav et al. 2014

Class "Methanonatronarchaeia"

Order "Methanonatronarchaeales"

  • Family Methanonatronarchaeaceae Sorokin et al. 2018
  • * "Candidatus Methanohalarchaeum" Sorokin et al. 2018
  • * Methanonatronarchaeum Sorokin et al. 2018

Class "Methanoliparia"

Order "Methanoliparales"

  • Family "Methanoliparaceae" Borrel et al. 2019
  • * "Candidatus Methanoliparum" Borrel et al. 2019
  • * "Candidatus Methanolliviera" Borrel et al. 2019

Class "[Archaeoglobi]a"

Order "Mnemosynellales"

  • Family "Mnemosynellaceae" Adam et al. 2022
  • * "Candidatus Mnemosynella" Adam et al. 2022

Order [Archaeoglobales]

  • Family "Allopolytropaceae" corrig. Boyd et al. 2019
  • * ?"Candidatus Allopolytropus" corrig. Boyd et al. 2019
  • Family Archaeoglobaceae Huber & Stetter 2002
  • * Archaeoglobus Stetter 1988
  • * Ferroglobus Hafenbradl et al. 1997
  • * Geoglobus Kashefi et al. 2002
  • * ?"Candidatus Methanoglobus" Buessecker et al. 2023
  • * ?"Candidatus Methanomixotrophus" corrig. Liu et al. 2021
  • * ?"Candidatus Methanoproducendum" Hua et al. 2019

Class "Syntropharchaeia"

Order "Aerarchaeales"

  • Family YL-1
  • * "Candidatus Methanodefluvium" Leu et al. 2025
  • Family "Aerarchaeaceae" Leu et al. 2025
  • * "Candidatus Aerarchaeum" Leu et al. 2025
  • * "Candidatus Aerovita" Leu et al. 2025

Order "Syntropharchaeales"

  • Family "Syntropharchaeaceae"
  • * "Candidatus Syntropharchaeum" corrig. Laso-Perez et al. 2016

Order "Alkanophagales"

  • Family "Methanophagaceae" Chadwick et al. 2022
  • * ?"Candidatus Methanoalium" Chadwick et al. 2022
  • * ?"Candidatus Methanophaga" Chadwick et al. 2022
  • Family ?"Veteromethanophagaceae" Vulcano et al. 2022
  • Family "Alkanophagaceae"
  • * "Candidatus Alkanophaga" Zehnle et al. 2023
  • Family "Methanospiraraceae" Laso-Pérez et al. 2022
  • * "Candidatus Methanospirare" Laso-Pérez et al. 2022
  • * "Candidatus Methanoxibalbensis" Laso-Pérez et al. 2022

Class Methanocellia

Order Methanocellales

  • Family Methanocellaceae Sakai et al. 2008
  • * Methanocella Sakai et al. 2008
  • * Methanooceanicella Zhang et al. 2024

Class Methanosarcinia

Order Methanotrichales

  • Family Methanotrichaceae Akinyemi et al. 2021
  • * "Candidatus Methanocrinis" Khomyakova et al. 2023
  • * Methanothrix Huser, Wuhrmann & Zehnder 1983

Order Methanosarcinales_A

Family Methermicoccaceae Cheng et al. 2007Methermicoccus Cheng et al. 2007

Order [Methanosarcinales]

  • Family "Methanogastraceae" corrig. Chadwick et al. 2022
  • * "Candidatus Methanogaster" Chadwick et al. 2022
  • Family "Methanocomedentaceae" corrig. Chadwick et al. 2022
  • * "Candidatus Methanocomedens" Chadwick et al. 2022
  • * "Candidatus Methanomarinus" Chadwick et al. 2022
  • Family "Ethanoperedentaceae" Pallen, Rodriguez-R & Alikhan 2022
  • * "Candidatus Ethaniperedens" corrig. Hahn et al. 2020
  • Family "Methanoperedentaceae" corrig. Haroon et al. 2013
  • * "Candidatus Methanoperedens" Haroon et al. 2013
  • Family Methanosarcinaceae Balch & Wolfe 1981
  • * ?Halomethanococcus Yu & Kawamura 1988
  • * Methanimicrococcus corrig. Sprenger et al. 2000
  • * Methanococcoides Sowers & Ferry 1985
  • * "Methanofrustulum" Protasov & Brune 2023
  • * Methanohalobium Zhilina & Zavarzin 1988
  • * Methanohalophilus Paterek & Smith 1988
  • * Methanolapillus Protasov & Brune 2025
  • * Methanolobus König & Stetter 1983
  • * Methanomethylovorans Lomans et al. 2004
  • * Methanosalsum Boone & Baker 2002
  • * Methanosarcina Kluyver & van Niel 1936
  • * ?"Candidatus Methanovorans" Chadwick et al. 2022

Class "[Methanomicrobia]"

Order [Methanomicrobiales]

Class "Hikarchaeia"

Order "Hikarchaeales"

  • Family "Hikarchaeaceae" Martijn et al. 2020
  • * ?"Candidatus Hikarchaeum" Martijn et al. 2020

Class "Ordosarchaeia"

Order "Ordosarchaeales"

  • Family "Ordosarchaeaceae" Zhao et al. 2024
  • * ?"Candidatus Ordosarchaeum" Zhao et al. 2024

Class [Halobacteria]

Order Halorutilales

  • Family Halorutilaceae Durán-Viseras et al. 2023
  • * "Candidatus Afararchaeum" Baker et al. 2024
  • * Halorutilus Durán-Viseras et al. 2023

Order [Halobacteriales]

  • ?"Haloalcalophilium" Lizama et al. 2000a
  • Family "Chewarchaeaceae" Baker et al. 2024
  • * "Candidatus Chewarchaeum" Baker et al. 2024
  • Family "Halalkalicoccaceae" Mao et al. 2025
  • * Halalkalicoccus Xue et al. 2005
  • * ?Natronorarus Mao et al. 2025
  • Family "Salinarchaeaceae"
  • * Salinarchaeum Cui et al. 2014
  • Family "Halostellaceae" Pallen, Rodriguez-R & Alikhan 2022
  • * Halostella Song et al. 2016
  • Family Natronoarchaeaceae Sorokin et al. 2023
  • * Natranaeroarchaeum Sorokin et al. 2023
  • * Natronoarchaeum Shimane et al. 2010
  • Family Natrialbaceae Gupta et al. 2015
  • * Haloarchaeobius Makhdoumi-Kakhki et al. 2012
  • * Halobiforma Hezayen et al. 2002
  • * Halomontanus Mao et al. 2024
  • * Halopiger Gutierrez et al. 2007
  • * Halorubellus Cui et al. 2014
  • * Halosolutus Sun et al. 2022
  • * Halostagnicola Castillo et al. 2006
  • * Haloterrigena Ventosa et al. 1999
  • * ?Halovalidus Dong et al. 2025
  • * Halovivax Castillo et al. 2006
  • * Natrarchaeobaculum Sorokin et al. 2020
  • * Natrarchaeobius corrig. Sorokin et al. 2020
  • * Natrialba Kamekura & Dyall-Smith 1996
  • * Natribaculum Liu et al. 2015
  • * Natronobacterium Tindall et al. 1984
  • * Natronobiforma Sorokin et al. 2019
  • * Natronococcus Tindall et al. 1984
  • * Natronolimnobius Itoh et al. 2005
  • * Natronolimnohabitans Sorokin et al. 2020
  • * Natrinema McGenity et al. 1998
  • * Natronobeatus Li et al. 2023
  • * Natrononativus Li et al. 2023
  • * Natronorubrum Xu et al. 1999
  • * Natronosalvus Tan et al. 2023
  • * Salinadaptatus Xue et al. 2020
  • * Salinilacihabitans Li et al. 2023
  • * Saliphagus Yin et al. 2017
  • Family Haladaptataceae Rinke et al. 2020
  • * Haladaptatus Savage et al. 2007
  • * Halomicrococcus Chen et al. 2020
  • * Halorussus Cui et al. 2014
  • Family Halobacteriaceae
  • * Halanaeroarchaeum Sorokin et al. 2016
  • * Halarchaeum Minegishi et al. 2010
  • * Halobacterium Elazari-Volcani 1957
  • * Halocalculus Minegishi et al. 2015
  • * Halodesulfurarchaeum Sorokin et al. 2017
  • * Halospeciosus Li et al. 2024
  • * Salarchaeum Shimane et al. 2011
  • Family Halococcaceae Gupta et al. 2016
  • * Halococcus Schoop 1935
  • Family Haloarculaceae
  • * Halapricum Song et al. 2014
  • * Haloarcula Torreblanca et al. 1986
  • * Halocatena Verma et al. 2020
  • * Halococcoides Sorokin et al. 2019
  • * Haloglomus Duran-Viseras, Sanchez-Porro & Ventosa 2020
  • * Halomarina Inoue et al. 2011
  • * Halomicroarcula Echigo et al. 2013
  • * Halomicrobium Oren et al. 2002
  • * Halorientalis Cui et al. 2011
  • * Halorarius Sun et al. 2023
  • * Halorhabdus Waino et al. 2000
  • * Halosegnis Duran-Viseras et al. 2022
  • * Halosimplex Vreeland et al. 2003
  • * Halovenus Makhdoumi-Kakhki et al. 2012
  • * Natronomonas Kamekura et al. 1997
  • * Salinibaculum Han & Cui 2020
  • * Salinirubellus Hou et al. 2018
  • * Salinirussus Cui et al. 2017
  • Family Haloferacaceae Gupta et al. 2015
  • * Halalkaliarchaeum Sorokin et al. 2019
  • * Halalkalirubrum Zuo et al. 2021
  • * ?"Candidatus Halectosymbiota" corrig. Filker et al. 2014
  • * Halegenticoccus Liu et al. 2022
  • * Halobaculum Oren et al. 1995
  • * Halobellus Cui et al. 2011
  • * Halobium Mori et al. 2016
  • * Haloferax Torreblanca et al. 1986
  • * Halogeometricum Montalvo-Rodriguez et al. 1998
  • * Halogranum Cui et al. 2010
  • * Halohasta Mou et al. 2013
  • * Halolamina Cui et al. 2011
  • * Halonotius Burns et al. 2010
  • * Haloparvum Chen et al. 2016
  • * Halopelagius Cui et al. 2010
  • * Halopenitus Amoozegar et al. 2012
  • * Haloplanus Elevi Bardavid et al. 2007
  • * Haloprofundus Zhang et al. 2017
  • * Haloquadratum Burns et al. 2007
  • * Halorubrum McGenity & Grant 1996
  • * Natronocalculus Sorokin et al. 2023
  • * ?Salinirarus Zhang et al. 2025
  • * Salinirubrum corrig. Cui & Qiu 2014
  • * Salinigranum Cui & Zhang 2014