Abstract
Me.tha.no.hal'ar.chae.um N.L. neut. n.
methanum
methane; N.L. pref.
methano
‐ pertaining to methane; Gr. masc. n.
hals, halos
salt; N.L. neut. n.
archaeum
(pertaining to
archaios, ‐e, ‐on)
ancient; N.L. neut. n.
Methanohalarchaeum
a salt‐loving archaeon forming methane.
The candidate genus
Ca
. Methanohalarchaeum includes obligately anaerobic, extremely halophilic, neutrophilic, and moderately thermophilic methanogens with small coccoid cells producing methane by reduction of C
1
‐methylated compounds using either H
2
or formate as electron donors. Amino acids or acetate is required as C‐source for assimilation. Core membrane lipids are represented by diphytanyl glycerol tetra‐ and diethers. Cells accumulate potassium as a compatible solute. They inhabit hypersaline lakes or salterns with neutral pH. The genus contains a single candidate species
Ca
. M. thermophilum, which is the type species. It is a member of the class
Methanonatronarchaeia
within a newly proposed phylum
Halobacteriota
(formerly part of the phylum
Euryarchaeota
).
DNA G + C content (mol%)
: 35.4 (genome of the type strain).
Type species
:
Ca
.
Methanohalarchaeum thermophilum
Sorokin, Merkel, Abbas, Makarova, Rijpstra et al. 2018, 2206.
Taxonomic and Nomenclature Notes
According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus
Candidatus Methanohalarchaeum
is: preferred name (not correct name) (last update, February 2025)
*
.
LPSN classification:
Archaea
/
Methanobacteriati
/
Methanobacteriota
/
Methanonatronarchaeia
/
Methanonatronarchaeales
/
Methanonatronarchaeaceae
/
Candidatus Methanohalarchaeum
The genus
Candidatus Methanohalarchaeum
can also be recovered in the Genome Taxonomy Database (GTDB) as
g__Methanohalarchaeum
(version v220)
**
.
GTDB classification:
d__Archaea
/
p__Halobacteriota
/
c__Methanonatronarchaeia
/
o__Methanonatronarchaeales
/
f__Methanonatronarchaeaceae
/
g__Methanohalarchaeum
*
Meier‐Kolthoff
et al. (
2022
).
Nucleic Acids Res
,
50
,
D801
–
D807
; DOI:
10.1093/nar/gkab902
**
Parks
et al. (
2022
).
Nucleic Acids Res
,
50
,
D785
–
D794
; DOI:
10.1093/nar/gkab776