Shell irregular, lobed or curved shapes with tetrahedrons, pyramids, discs or plates, 0.5 to 2 microns wide. Gram-negative, non-motile. The cell wall is surrounded by a thin shell of 2 nm in thickness composed of subunits hexagonal. Facultative aerobic. Aerobic growth by oxidation of elemental sulfur or by sulfo-reducing anaerobic. Autotrophic growth and mixotrophic on yeast extract without sulfur aerobically. Organisms thermoacidophiles increasing between 45 and 96 ° C and pH 1 to 6, in the presence of 1 to 40 g / l of NaCl. DNA contains 31 mol% G+ C. Four species isolated solfatars acids and submarine hydrothermal vents, which Acidianusinfernus .
