Fig. 4 in New psittacosaurid highlights skull enlargement in horned dinosaurs

Fig. 4. Skull size in ceratopsians. A. Human silhouette (1.68 m) compared to an adult skull of the frilled ceratopsian Pentaceratops sternbergi (after Lehman 1998). B. Relationships among ceratopsians showing the shift to an obligate quadrupedal posture among neoceratopsians and stepwise increase in skull size (skull size shown as a percent of trunk length).