Archaea classes

Haloarchaea (halophilic archaea, halophilic archaebacteria, halobacteria) are a class of archaea under the phylum Euryarchaeota, found in water saturated or nearly saturated with salt. 'Halobacteria' are now recognized as archaea rather than bacteria and are one of the largest groups of archaea. The name 'halobacteria' was assigned to this group of organisms before the existence of the domain Archaea was realized, and while valid according to taxonomic rules, should be updated. Halophilic archaea are generally referred to as haloarchaea to distinguish them from halophilic bacteria.

Thermoplasmata is a class of archaeans in the phylum Thermoplasmatota.

The Thermoprotei is a class of the Thermoproteota.

thumb|Schematic diagram of the Thermococcus gammatolerans cell pictured above. thumb|Pyrococcus furiosus

"Methanomicrobia" is a class of archaeans in the phylum Methanobacteriota.

Methanobacteria is a class of archaeans in the kingdom "Euryarchaeota". Several of the classes of the "Euryarchaeota" are methanogens and the Methanobacteria are one of these classes.

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REDIRECT Archaeoglobaceae

Methanopyri is a class of archaeans in the phylum Methanobacteriota.

"Thorarchaeia" is a class within the kingdom Promethearchaeati. The kingdom Promethearchaeati represents the closest prokaryotic relatives of eukaryotes. Since there is such a close relation between the two different domains, it provides further evidence for the two-domain tree of life theory which states that eukaryotes branched from the archaeal domain. Kingdom Promethearchaeati are single cell marine microbes that contain branch-like appendages and have genes that are similar to Eukarya. The kingdom Promethearchaeati is composed of "Thorarchaeia", Promethearchaeia, "Odinarchaeia", and "Heim

Nanohalarchaeota is a phylum of diminutive archaea with small genomes and limited metabolic capabilities, belonging to kingdom Nanobdellati. They are ubiquitous in hypersaline habitats, which they share with the extremely halophilic haloarchaea.

Promethearchaeaceae (previously called "Lokiarchaeota") is a family of the kingdom Promethearchaeati, the kingdom from which the eukaryotes emerged. The family includes all members of the group previously named Deep Sea Archaeal Group, also known as Marine Benthic Group B. A phylogenetic analysis disclosed a monophyletic grouping of the Promethearchaeaceae with the eukaryotes. The analysis revealed several genes with cell membrane-related functions. The presence of such genes support the hypothesis of an archaeal host for the emergence of the eukaryotes: the eocyte-like scenarios.