Riojasaurus had a heavy body, bulky legs, and a long neck and tail. Its leg bones were dense and massive for a prosauropod.[1] By contrast, its vertebrae were lightened by hollow cavities, and unlike most prosauropods, Riojasaurus had four sacral vertebrae instead of three.[1] It probably moved slowly on all fours and was unable to rear up on its back legs.[1][2] The nearly equal length of the fore and hindlimbs[1] is also suggestive of an obligatorily quadrupedal gait.