Archaea phyla

Nanobdellota (previously "Nanoarchaeota", Greek for "dwarf or tiny ancient one") is a phylum of Archaea. The first species discovered, Nanoarchaeum equitans, was from a submarine hydrothermal vent in Iceland and described in 2002. The name of the phylum is derived from the species Nanobdella (Greek nânos, a dwarf; bdella, leech) aerobiophila discovered from a terrestrial hot spring in Japan.

Methanobacteriota is a phylum in the domain Archaea. The phylum was introduced to prokaryotic nomenclature in 2023.

The Thermoproteota are archaea that have been classified as a phylum of the domain Archaea. Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteristic Thermoproteota environmental rRNA indicating the organisms may be the most abundant archaea in the marine environment. Originally, they were separated from the other archaea based on rRNA sequences; other physiological features, such as lack of histones, have supported this division, although some crenarchaea were found to have histones. Until 2005 all cultured Thermoproteota

"Parvarchaeota" is a phylum of archaea belonging to the Nanobdellati kingdom. They have been discovered in acid mine drainage waters and later in marine sediments. The cells of these organisms are extremely small consistent with small genomes. Metagenomic techniques allow obtaining genomic sequences from non-cultured organisms, which were applied to determine this phylum.