Bunostegos

Bunostegos ("knobbly [skull] roof") is an extinct genus of pareiasaur parareptile from the Late Permian of the Agadez Region in Niger. The type species, Bunostegos akokanensis, was named from the Moradi Formation in 2003. It was a cow-sized animal with a distinctive skull that had large bony knobs, similar in form to those of other pareiasaurs but far larger. The species appears to have lived in a desert in the centre of the supercontinent of Pangaea.

Analysis of the limb bones (including the scapulocoracoid, humerus, radius, ulna, pelvis, and femur) was published in 2015, and revealed that Bunostegos walked upright on four limbs, with the body held above ground. This new information directly suggests that it could be the first tetrapod with a fully erect gait.