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 (LPSN) and National Center for Biotechnology Information (NCBI) unless otherwise noted.
Phylogeny For the GTDB 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 the GTDB release 11-RS232 (15th April 2026).
Phylum Microcaldota Class Microcaldia Order Microcaldales Family Microcaldaceae Sakai et al. 2023 Microcaldus Sakai et al. 2023
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"
Class "Aenigmatarchaeia" Order "Aenigmatarchaeales" Family "Aenigmatarchaeaceae" corrig. Rinke et al. 2020 "Candidatus Aenigmatarchaeum" corrig. Rinke et al. 2013 Order PWEA01 Family "Haloaenigmatarchaeaceae" Gutiérrez-Preciado et al. 2024 [PWEA01] "Candidatus Haloaenigmatarchaeum" Gutiérrez-Preciado et al. 2024
Phylum "Terrarchaeota"
Class "Terrarchaeia" Order "Terrarchaeales" Family "Marinivulcanaceae" Hamm et al. 2026 [WAPT01] "Candidatus Marinivulcanus" Hamm et al. 2026 [WAPT01] Family "Terrarchaeaceae" Hamm et al. 2026 ["Caliditerrarchaeaceae" Hamm et al. 2025; GLR71] "Candidatus Terrarchaeum" Hamm et al. 2026 ["Candidatus Caliditerrarchaeum" Hamm et al. 2025; GLR71]
Phylum "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 "Nanohalalkaliarchaeaceae" La Cono et al. 2020 "Candidatus Nanohalalkaliarchaeum" Ghai et al. 2011 Family "Nanoanaerosalinaceae" Zhao et al. 2022 "Candidatus Asbonarchaeum" Baker et al. 2024 "Candidatus Nanoanaerosalina" Zhao et al. 2022 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
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 ["Nanopusillaceae" Huber et al. 2011] Nanobdella Kato et al. 2022 ["Ca. Nanobsidianus" Castelle et al. 2015; "Ca. Nanopusillus" Wurch et al. 2016] "Candidatus Nanoclepta" St. John et al. 2019
Order "Tiddalikarchaeales" Family "Tiddalikarchaeaceae" Vázquez-Campos et al. 2021 "Candidatus Tiddalikarchaeum" Vázquez-Campos et al. 2021
Order JAPDLS01 Family "Haiyanarchaeaceae" Rao et al. 2023 "Candidatus Haiyanarchaeum" Rao et al. 2023 ["Ca. Tinosarcha" Pallen, Rodriguez-R & Alikhan 2022]
Order "Jingweiarchaeales" Family "Jingweiarchaeaceae" Rao et al. 2023 "Candidatus Jingweiarchaeum" Rao et al. 2023
Order "Parvarchaeales" Family "Parvarchaeaceae" Rinke et al. 2020 "Candidatus Acidifodinimicrobium" Luo et al. 2020 "Candidatus Parvarchaeum" Baker et al. 2010 (ARMAN 4 & 5) "Candidatus Rehaiarchaeum" Rao et al. 2023
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 [CSSED10-239] "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 "Burarchaeales" Family "Gugararchaeaceae" Vázquez-Campos et al. 2021 "Candidatus Gugararchaeum" Vázquez-Campos et al. 2021 Family "Burarchaeaceae" Vázquez-Campos et al. 2021 "Candidatus Burarchaeum" Vázquez-Campos et al. 2021 Family "Fermentimicrarchaeaceae" Kadnikov et al. 2020 (Sv326) "Candidatus Fermentimicrarchaeum" Kadnikov et al. 2020
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 ?"Kexuearchaeota" Cai et al. 2021 ?"Sleipnirarchaeota" Kioukis et al. 2025 ?"Candidatus Balderarchaeum" Xie et al. 2022 ?"Candidatus Ranarchaeum" Appler et al. 2026 ?"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 "Thorarchaeia" Order "Thorarchaeales" Family "Thorarchaeaceae" (MBG-B)
Class "Atabeyarchaeia" Order "Atabeyarchaeales" Family "Atabeyarchaeaceae" Valentin-Alvaradoet al. 2024 "Candidatus Atabeyarchaeum" Valentin-Alvarado et al. 2024
Class "Baldrarchaeia" Order "Baldrarchaeales" Family "Baldrarchaeaceae" corrig. Liu et al. 2021 "Candidatus Baldrarchaeum" Liu et al. 2021
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 ["Ca. Freyarchaeum" (sic) Valentin-Alvarado et al. 2024]
Class "Odinarchaeia" Order "Odinarchaeales" Family "Odinarchaeaceae" Tamarit et al. 2022 "Candidatus Odinarchaeum" Tamarit et al. 2022
Order "Yangjianarchaeales"
Class "Hermodarchaeia" Order "Hermodarchaeales" Family "Hermodarchaeaceae" corrig. Liu et al. 2021 "Candidatus Hermodarchaeum" Liu et al. 2021
Class Promethearchaeia Order "Helarchaeales"
Order 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 (MBGB, DSAG) "Candidatus Nerearchaeum" Nobs et al. 2026 Promethearchaeum Imachi et al. 2024
Class "Borrarchaeia" 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" ?"Candidatus Yibarchaeum" MacLeod et al. 2025 Order "Wenzhongarchaeales"
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 "Gerdarchaeales"
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
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
Thermoproteota Incertae sedis "Brockiarchaeota"
Class CALKCG01 Order "Bifangarchaeales" Family "Bifangicolaceae" Hou et al. 2023 ?"Candidatus Bifangicola" Hou et al. 2023 [3300025546_26] Family "Bifangarchaeaceae" Hou et al. 2023 [B24] "Candidatus Bifangarchaeum" corrig. Hou et al. 2023 [DTBU01 sp011374155] Family "Bifangistellaceae" Hou et al. 2023 [DRYS01] "Candidatus Bifangistella" Hou et al. 2023 [DRYS01 sp011367275]
Class "Bathyarchaeia" 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 [RBG-16-48-13 sp001775995]
Order "Hecatellales"
Family "Hecatellaceae" Rinke et al. 2020 ["Jinwuarculaceae" Hou et al. 2023; "Jinwuicolaceae" Hou et al. 2023; "Jinwuimonadaceae" Hou et al. 2023; "Jinwuiprofundaceae" Hou et al. 2023; "Jinwuousiaceae" Hou et al. 2023] "Candidatus Hecatella" Adam et al. 2022 "Candidatus Jinwuarcula" Hou et al. 2023 [B25] "Candidatus Jinwuicola" Hou et al. 2023 [EX4484-218 sp002254975] ?"Candidatus Jinwuimonas" Hou et al. 2023 "Candidatus Jinwuimorpha" Hou et al. 2023 [EX4484-218 sp003661965] ?"Candidatus Jinwuiprofundus" Hou et al. 2023 ?"Candidatus Jinwuousia" Hou et al. 2023 [JdFR-11 sp002011035]
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 [DTDX01] Family "Fontihoutuithermaceae" Hou et al. 2023 ["Fluxihoutuithermaceae" Hou et al. 2023; DTGE01] ?"Candidatus Fluxihoutuithermus" Hou et al. 2023 [DTOY01 sp011358085] "Candidatus Fontihoutuithermus" Hou et al. 2023 [DTGE01 sp011389385] Family "Aphrohoutuibellaceae" Hou et al. 2023 [RBG-13-38-9] "Candidatus Aphrohoutuibellus" Hou et al. 2023 [RBG-13-38-9] "Candidatus Hydrohoutuibellus" Hou et al. 2023 [DTMT01 sp011355205] Family "Houtuousiaceae" Hou et al. 2023 ["Houtuarculaceae" Hou et al. 2023; "Limnohoutuiplasmataceae" corrig. Hou et al. 2023; 40CM-2-53-6] "Candidatus Houtuousia" Hou et al. 2023 [40CM-2-53-6]