Promethearchaeota

Promethearchaeota is the sole phylum of the kingdom Promethearchaeati, the kingdom from which the eukaryotes emerged. The phylum has one valid class: Promethearchaeia. The phylum 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 Promethearchaeota 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.

Promethearchaeota was introduced in 2015 after the identification of a candidate genome in a metagenomic analysis of a mid-oceanic sediment sample. This analysis suggests the existence of a genus of unicellular life dubbed Lokiarchaeum. The sample was taken near a hydrothermal vent at a vent field known as Loki's Castle located at the bend between Mohns/Knipovich ridge in the Arctic Ocean.