acidianus infernus acidianus infernus acidianus infernus is a species of archaeon. it is aerobic, extremely acidophilic, thermophilic (hence its name) and sulfur-metabolizing. its type strain is strain dsm 3191. acidianus infernus scientific classification domain: archaea phylum: thermoproteota class: thermoprotei order: sulfolobales family: sulfolobaceae genus: acidianus species: a. infernus binomial name acidianus infernussegerer et al., 1986