euryarchaeota euryarchaeota euryarchaeota (from ancient greek εὐρύς eurús, "broad, wide") is a phylum of archaea. euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °c. they are separated from the other archaeans based mainly on rrna sequences and their unique dna polymerase. euryarchaeota halobacterium sp. strain nrc-1, each cell about 5 µm in length. scientific classification domain: archaea kingdom: euryarchaeotawoese, kandler & wheelis, 1990 phyla "hydrothermarchaeota" "hadarchaeota" "methanobacteriota" "thermoplasmatota" "halobacteriota" ?theionarchaea ?dpann synonyms non euryarchaeota s.s. garrity and holt 2002 euryarchaeida luketa 2012 methaneocreatrices margulis & schwartz 1982 description the euryarchaeota are diverse in appearance and metabolic properties. the phylum contains organisms of a variety of shapes, including both rods and cocci. euryarchaeota may appear either gram-positive or gram-negative depending on whether pseudomurein is present in the cell wall. euryarchaeota also demonstrate diverse lifestyles, including methanogens, halophiles, sulfate-reducers, and extreme thermophiles in each. others live in the ocean, suspended with plankton and bacteria. although these marine euryarchaeota are difficult to culture and study in a lab, genomic sequencing suggests that they are motile heterotrophs. though it was previously thought that euryarchaeota only lived in extreme environments (in terms of temperature, salt content and/or ph), a paper by korzhenkov et al published in january 2019 showed that euryarchaeota also live in moderate environments, such as low-temperature acidic environments. in some cases, euryarchaeota outnumbered the bacteria present. euryarchaeota have also been found in other moderate environments such as water springs, marshlands, soil and rhizospheres. some euryarchaeota are highly adaptable; an order called halobacteriales are usually found in extremely salty and sulfur-rich environments but can also grow in salt concentrations as low as that of seawater 2.5%. in rhizospheres, the presence of euryarchaeota seems to be dependent on that of mycorrhizal fungi; a higher fungal population was correlated with higher euryarchaeotal frequency and diversity, while absence of mycorrihizal fungi was correlated with absence of euryarchaeota. phylogeny the currently accepted taxonomy is based on the list of prokaryotic names with standing in nomenclature (lpsn) and national center for biotechnology information (ncbi) 16s rrna based ltp_12_2021. dombrowski et al. 2019, jordan et al. 2017 and cavalier-smith2020. archaea methanopyri tack nitrososphaerota thermoproteota euryarchaeota methanococci thermoplasmata archaeoglobi thermococci methanobacteria methanonatronarchaeia methanomicrobia halobacteria other phylogenetic analyzes have suggested that the archaea of the clade dpann may also belong to euryarchaeota and that they may even be a polyphyletic group occupying different phylogenetic positions within euryarchaeota. it is also debated whether the phylum altiarchaeota should be classified in dpann or euryarchaeota. a cladogram summarizing this proposal is graphed below. the groups marked in quotes are lineages assigned to dpann, but phylogenetically separated from the rest. archaea euryarchaeota thermococci hadesarchaea methanobacteria methanopyri methanococci thermoplasmata archaeoglobi methanomicrobia "nanohaloarchaeota" haloarchaea "altiarchaeota" dpann diapherotrites micrarchaeota undinarchaeota aenigmarchaeota nanoarchaeota parvarchaeota mamarchaeota pacearchaeota woesearchaeota proteoarchaeota tack asgard lokiarchaeota odinarchaeota thorarchaeota heimdallarchaeota (+α─proteobacteria) eukaryota a third phylogeny, 53 marker proteins based gtdb 07-rs207. archaea "dpann" proteoarchaeota "tack" asgardaeota "euryarchaeida" hadarchaeota "hadarchaeia" (sagmeg) "acherontia" thermococci "methanomada" methanobacteriota_a methanopyri methanococci hydrothermarchaeota "hydrothermarchaeia" (mbg-e) "methanobacteriota" methanobacteria (class i methanogens) "neoeuryarchaeota" "thermoplasmatota" "izemarchaea" "pontarchaea" (mgiii) "poseidoniia" (mgii) thermoplasmata "halobacteriota" "methanoliparia" archaeoglobi "syntropharchaeia" (anme-1, anme-2) "methanocellia" "methanosarcinia" "methanomicrobia" methanonatronarchaeia (sa1) halobacteria (class ii methanogens) euryarchaeota s.s.