Cultivated members of this genus are thermophilic, microaerophilic, and autotrophic. Metagenome-assembled genomes representing members of the genus were also recovered from environmental samples consistent with these traits. Species in the genus encode genes for all five complexes of the electron transport chain, with cultivated members using oxygen as terminal electron acceptor. They are chemolithoautotrophic, with genes coding for components of the reductive tricarboxylic acid cycle conserved within the genus, likely using either hydrogen or thiosulfate as electron donors. Most members of the genus encode [NiFe] Group 1d and [NiFe] 2d uptake hydrogenases, and all species encode genes for the SOX complex for thiosulfate oxidation, and sulfide:quinone oxidoreductase (sqr) for sulfide oxidation. Cultivated members are capable of chemolithoheterotrophy using acetate. Vitamins are not required for growth. Cultivated members are negative for Gram-staining reaction, and spores are not formed. Cells are rod-shaped and motile via one or more polar flagella. Most species also encode genes required for flagellar motility. Relative evolutionary divergence places these members in a novel genus-level group and phylogenomic placement of this genus is within the Aquificaceae.