Stygiolobus Segerer et al. 1991 Stygiolobus azoricus Segerer et al. 1991 Universal Root Woese et al. 1990 Archaea Woese et al. 1990 Crenarchaeota (sic) Garrity and Holt 2021 Thermoproteota corrig. Garrity and Holt 2021 Thermoprotei Reysenbach 2002 Sulfolobales Stetter 1989 Sulfolobaceae Stetter 1989 Stygiolobus Segerer et al. 1991 Sulfolobaceae Stetter 1989 Sulfurisphaera Kurosawa et al. 1998 emend. Tsuboi et al. 2018 Acidianus (sic) Segerer et al. 1986 emend. Plumb et al. 2007 Acidijanus corrig. Segerer et al. 1986 emend. Plumb et al. 2007 Metallosphaera Huber et al. 1989 Sulfurococcus Golovacheva et al. 1995 Sulfolobus Brock et al. 1972 (Approved Lists 1980) Desulfurolobus Zillig et al. 1987 Sulfodiicoccus Sakai and Kurosawa 2017 Saccharolobus Sakai and Kurosawa 2018 Sulfuracidifex Itoh et al. 2020 Stygiolobus azoricus Segerer et al. 1991 Segerer A.H. Trincone A. Gahrtz M. Stetter K.O. Stygiolobus azoricus gen. nov., sp. nov. represents a novel genus of anaerobic, extremely thermoacidophilic archaebacteria of the order Sulfolobales. 1991 41 4 495 501 International Journal of Systematic Bacteriology Int J Syst Bacteriol 0020-7713 10.1099/00207713-41-4-495