class members originating at sites within the Pacific Ring of Fire and other tectonically active locations and description of the novel genus '.

Recent studies have expanded the genomic contours of the , highlighting important lacunae in our comprehension of the phylogenetic space occupied by certain lineages of the class. One such lineage is ', a novel genus-level taxon, represented by ' VAN18-1 as its type species, along with two other uncultivated metagenome-assembled genomes (MAGs) originating from geothermally active sites across the Pacific Ring of Fire. In this study, we investigate the genetic and genomic diversity, and the distribution patterns of several uncharacterized class strains and sequence clones, which are ascribed to the same 16S rRNA gene sequence clade.