Figure 5.

On the plot of mandible shape variance across PCs 1 and 2 for Papio and Pan, PC1 describes variance that is closely associated with ontogenetic growth. The scatters of Papio and Pan do not overlap; the angle between both scatters is statistically significant, indicating that the mandibles of each genus follow different ontogenetic trajectories to different adult shapes (wireframes, upper left). Both scatters are linear. Thus, mandible growth trajectory is established at or before birth. Red squares, Pan paniscus; teal diamonds, Pan troglodytes; blue triangles, Papio anubis.