Description of <i>Asgardarchaeum abyssi</i> gen. nov. spec. nov., a novel species within the class Asgardarchaeia and phylum Asgardarchaeota in accordance with the SeqCode

<i>Asgardarchaeota</i>, commonly referred to as Asgard archaea, is a candidatus phylum-rank archaeal clade that includes the closest archaeal relatives of eukaryotes. Despite their prevalence in the scientific literature, the name <i>Asgardarchaeota</i> lacks nomenclatural validation. Here, we describe a novel high-quality metagenome-assembled genome (MAG), AB3033_2^TS, proposed to serve as the nomenclatural type for the species <i>Asgardarchaeum abyssi</i>^TS according to the rules of the SeqCode. Based on protein content and compositional features, we infer that <i>A. abyssi</i> AB3033_2^TS is an acetogenic chemoheterotroph, possibly a facultative lithoautotroph, and is adapted to a thermophilic lifestyle. Utilizing genomes from Asgard archaea, TACK, and Euryarchaea, we perform phylogenomic reconstructions using the GTDB archaeal marker genes, the current reference set for taxonomic classification. Calibrating relative evolutionary divergence (RED) values for <i>Asgardarchaeota</i> using established <i>Thermoproteota</i> lineages in the GTDB r207 reference tree, we establish a robust classification and propose <i>Asgardarchaeum</i> as the type genus for the family <i>Asgardarchaeaceae</i><i> </i>(fam. nov)., the order <i>Asgardarchaeales</i><i> </i>(ord. nov.), the class <i>Asgardarchaeia</i> (class. nov.), and the phylum <i>Asgardarchaeota</i><i> </i>(phyl. nov.). This effort aims to preserve taxonomic congruence in the scientific literature.