The Amanasaurus holotype specimen, CAPPA/UFSM 0374, was discovered in the Hyperodapedon Assemblage Zone of the Santa Maria Supersequence (Candelária Sequence) of the Paraná Basin, dated to the late Carnian stage of the Late Triassic. It consists of a proximal right femur. CAPPA/UFSM 0375, a distal left femur belonging to a larger individual from the same locality, was also referred to Amanasaurus.
