 Several early studies suggested that heterodontosaurids were very primitive ornithischians.Due to supposed similarities in the morphology of the forelimbs, Robert Bakker proposed a relationship between heterodontosaurids and early sauropodomorphs like "Anchisaurus", bridging the orders Saurischia and Ornithischia.The dominant hypothesis over the last several decades has placed heterodontosaurids as basal ornithopods.