"Abrictosaurus" is usually thought to be the most basal member of the family Heterodontosauridae. "Lycorhinus" and "Heterodontosaurus" both had high-crowned cheek teeth, which went over each other in the jaw, making a continuous chewing surface analogous to those of Cretaceous hadrosaurids. "Abrictosaurus" had more widely-split cheek teeth, with lower crowns, more similar to other early ornithischians. 