SciencePhysicsChemistry ► Organic Chemistry ► BiologyExtremophiles



This page is under construction.


Acidophiles: This group includes organisms capable of thriving in hyperacidic conditions, most of which have an optimal growth pH of 5 or lower (OGpH<5)

Hyperacidotolerant, near-acidophilic neutriphiles: This group includes organisms that have an OGpH slightly above this (e.g., Nanoarchaeum equitans, OGpH=6) but can nonetheless be found flourishing in hyperacidic environments (pH=0.5-1.5).

Taxonomic/Phylogenetic Overview of Hypergeophilic & Hypergeotolerant Genera

“Hypergeophilic genera” and “hypergeotolerant genera” refer here to genera known to include hypergeophilic species and/or species with hypergeotolerances.

Genera containing thermophilic and hyperthermotolerant organisms are marked with an asterisk (*)

Genera containing barophilic and hyperbarotolerant organisms are marked with two asterisks (**)

Genera containing acidophilic and hyperacidotolerant organisms are marked with a dagger (†)

Genera containing alkaliphilic and hyperalkalitolerant organisms are marked with two daggers (††)

Genera containing thermoacidophilic and hyperthermoacidotolerant organisms are marked with an asterisk and a dagger (*†)

Genera containing halophilic and hyperhalotolerant organisms are marked with a double dagger (‡)

Bacteria marked with an asterisk and a degree sign (*°) are endospore-forming polyextremotolerant organisms. Bacterial endospores tend to give the bacteria capable of producing them polyextremotolerance. Endospores are known for being able to survive extremely high doses of radiation, vacuum dessication, extreme heat and cold, lack of nutrients, and in some cases even the passage of hundreds of millions of years (for example, Virgibacillus marismortui (formerly Bacillus marismortui and Bacillus strain 2-9-3) was revived by scientists from 250-million-year-old spores (Vreeland, 2000); for comparison, the first dinosaurs began appearing about 220 MYA — 30 million years later). Although these endospore-forming bacteria can survive a variety of harsh conditions, endospore-formation is not done for reproduction, as with fungal spore formation, but is instead a last-ditch effort to survive conditions the bacterium would not otherwise be able to, which means these critters aren’t true polyextremophiles, because they don’t (necessarily) actually grow better in extreme conditions, and in their endospore form don’t even grow at all.

In addition to other sources cited, much of this information was compiled with the help of NCBI’s Taxonomy Browser.

Domain: Archaea
Phylum: Euryarchaeota
Class: Archaeoglobi
Order: Archaeoglobales
Family: Archaeoglobaceae
Genus: Archaeoglobus *
Class: Stenosarchaea
Order: Candidatus Nanohaloarchaeota
Family: Nanohaloarchaea
Genus: Haloredivivus †‡
Genus: Nanosalina *†‡
Genus: Nanosalinarum †‡
Class: Halobacteria
Order: Halobacteriales
Family: Haloarculaceae
Genus: Haloarcula
Genus: Halorhabdus
Genus: Halorientalis
Genus: Halosimplex
Genus: Natronomonas ††‡
Family: Halobacteriaceae
Genus: Haladaptatus
Genus: Halalkalicoccus ††‡
Genus: Halarchaeum †‡
Genus: Haloalcalophilum ††‡
Genus: Halobacterium
Genus: Halomarina
Genus: Halorussus
Genus: Natronoarchaeum
Genus: Salarchaeum
Family: Halococceae
Genus: Halococcus
Order: Haloferacales
Family: Haloferacaceae
Genus: Halobellus
Genus: Haloferax
Genus: Halopelagius
Genus: Haloplanus
Genus: Haloquadratum
Family: Halorubraceae
Genus: Halobaculum
Genus: Halogeometricum
Genus: Halogranum
Genus: Halolamina
Genus: Halonotius
Genus: Halorubrum ††‡
Order: Natrialbales
Family: Natrialbaceae
Genus: Halobiforma
Genus: Halopiger
Genus: Halostagnicola
Genus: Haloterrigena
Genus: Halovivax
Genus: Natrarchaeobaculum
Genus: Natrialba ††‡+
Genus: Natrinema
Genus: Natronobacterium ††‡
Genus: Natronococcus ††‡
Genus: Natronolimnohabitans
Genus: Natronolimnobius
Genus: Natronorubrum
Class: Methanococci
Order: Methacoccales
Family: Methanococcaceae
Genus: Methanocaldococcus ***
Class: Methanopyri
Order: Methanopyrales
Family: Methanopyraceae
Genus: Methanopyrus *
Class: Thermococci
Order: Thermococcales
Family: Thermococcaceae
Genus: Pyrococcus ***
Genus: Thermococcus ***†††
Class: Thermoplasmata
Order: Methanomassiliicoccales
Family: Methanomassiliicoccaceae
Genus: Methanomassiliicoccus
Order: Thermoplasmatales
Family: Cuniculiplasmaceae
Genus: Cuniculiplasma
Family: Ferroplasmaceae
Genus: Acidiplasma
Genus: Ferroplasma
Family: Picrophilaceae
Genus: Picrophilus
Family: Incertae sedis
Genus: Thermogymnomonas
Superphylum: DPANN group
Phylum: Candidatus Diapherotrites
Class: Incertae sedis
Order: Incertae sedis
Family: Incertae sedis
Genus: Iainarchaeum
Phylum: Aenigarchaeota
Class: (unnamed?)
Order: Aenigmarchaeales
Family: (unnamed?)
Genus: Aenigmarchaeum
Phylum: Nanoarchaeota
Class: (unnamed?)
Order: Nanoarchaeales
Family: Nanoarchaeaceae
Genus: Nanoarchaeum *†
Family: Nanopusillaceae
Genus: Nanobsidianus *†
Genus: Nanopusillus *†
Phylum: Incertae sedis
Class: Incertae sedis
Order: Incertae sedis
Family: Incertae sedis
Genus: Candidatus Mancarchaeum †
Phylum: Candidatus Micrarchaeota
Class: Incertae sedis
Order: Incertae sedis
Family: Incertae sedis
Genus: Candidatus Micrarchaeum †
Phylum: Candidatus Parvarchaeota
Class: Incertae sedis
Order: Incertae sedis
Family: Incertae sedis
Genus: Candidatus Parvarchaeum †
Kingdom: Proteoarchaeota (93x; 60*, 57†, 24*†)
Superphylum: TACK group (93x; 60*, 57†, 24*†)
Phylum: Thaumarchaeota (23x; 23†)
Class: Nitrososphaeria (15x; 15†)
Order: Nitrosopumilales (11x; 11†)
Family: Nitrosopumilaceae (11x; 11†)
Genus: Candidatus Nitrosoarchaeum (3x; 3†)
Genus: Nitrosopumilus (8x; 8†)
Order: Nitrososphaerales (4x; 4†)
Family: Nitrososphaeraceae (4x; 4†)
Genus: Candidatus Nitrosocosmicus (1x; 1†)
Genus: Candidatus Nitrososphaera (3x; 3†)
Class: Incertae sedis
Order: Incertae sedis
Family: Incertae sedis
Genus: Candidatus Nitrosopelagicus (1x; 1†)
Class: Incertae sedis
Order: Incertae sedis
Family: Incertae sedis
Genus: Candidatus Nitrosotalea (4x; 4†)
Class: Incertae sedis
Order: Incertae sedis
Family: Incertae sedis
Genus: Candidatus Nitrosotenuis (3x; 3†)
Phylum: Crenarchaeota (70x; 60*, 34†, 24*†)
Class: Thermoprotei (69x; 60*, 33†, 24*†)
Order: Desulfurococcales (4x; 4*)
Family: Desulfurococcacae (2x; 2*)
Genus: Aeropyrum (2x; 2*)
Family: Pyrodictiacae (2x; 2*)
Genus: Geogemma (1x; 1*)
Genus: Pyrolobus (1x; 1*)
Order: Sulfolobales (65x; 56*, 33†, 24*†)
Family: Sulfobaceae (65x; 56*, 33†, 24*†)
Genus: Acidianus (10x; 10*†)
Genus: Metallosphaera (5x; 5†)
Genus: Stygiolobus (1x; 1*†)
Genus: Sulfolobus (45x; 45*, 13†, 13*†)
Genus: Sulfurisphaera (1x; 1†)
Genus: Sulfurococcus (3x; 3†)
Class: Incertae sedis
Order: Cenarchaeales (1x; 1†)
Family: Cenarchaeaceae (1x; 1†)
Genus: Cenarchaeum (1x; 1†)

Alphabetical List

Described Species
Genus & Species Temperature
T°C range
kPa range
pH range
aw range
%NaCl range
Gy range
low_T°C OGT°C high_T°C low_kPa OGkPa high_kPa min._pH OGpH max._pH low_aw OGaw high_aw low_NaCl OGNaCl high_NaCl low_Gy OGGy high_Gy
Candidatus_Aenigmarchaeum_subterraneum - - - - - - - 0.5-1.5 - - - - - - - - - -

In-Line Citations by Genus & species

Described Species
Genus & Species Source
Candidatus Aenigmarchaeum subterraneum Baker &al., 2006; Golyshina &al., 2017

Full Citations

Schuerger & Nicholson, 2016.

Nicholson &al., 2013.

Golyshina, O.V.; Yakimov, M.M.; Lunsdorf, H.; Ferrer, M; Nimtz, M.; Timmis, K.N.; Wray, V.; Tindall, B.J.; Golyshin, P.N.; (2009); Acidiplasma aeolicum gen. nov., sp. nov., a euryarchaeon of the family Ferroplasmaceae isolated from a hydrothermal pool, and transfer of Ferroplasma cupricumulans to Acidiplasma cupricumulans comb. nov

Radioresistant Organisms
⚑ = You Are Here.

LUCA: The Last Universal Common Ancestor
The New Spontaneous Generation? "Early-Complexity" Hypotheses for Primordial Life

Journal Links
Nature: International Journal of Science
PMC — PubMed Central
PNAS — Proceedings of the National Academy of Sciences of the United States of America

Catalogue Links
Bone Clones
Skulls Unlimited
The TeacherSource
ThermoFisher Scientific

Magazine Links
National Geographic
Popular Science
Scientific American

Evolution Links
The Phylogeny Explorer Project
Tree of Life Web Project

About GenPan
The Official FAQ

Donate $ to D. J. Scott
Donate an Article
Donate an Image

Social Media Groups