Iainarchaeota

Nanobdellati (syn. "DPANN") is a kingdom of archaea first proposed in 2013. Many members show novel signs of horizontal gene transfer from other domains of life. They are known as nanoarchaea or ultra-small archaea due to their smaller size (nanometric) compared to other archaea.

"DPANN" is an acronym formed by the initials of the first five groups discovered: Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota and Nanohaloarchaeota. Later Woesearchaeota and Pacearchaeota were discovered and proposed within the "DPANN" superphylum. In 2017, another phylum Altiarchaeota was placed into the "DPANN" superphylum. The monophyly of Nanobdellati is not yet considered established, due to the high mutation rate of the included phyla, which can lead to the artifact of the long branch attraction (LBA) where the lineages are grouped basally or artificially at the base of the phylogenetic tree without being related. These analyses instead suggest that Nanobdellati belongs to Euryarchaeota or is polyphyletic occupying various positions within Euryarchaeota.