Figure 4.

Visualizations of the main effects of skull size, gender and directionality of the cross on skull shape. The model is the shape resulting from the addition of the effect to the mean shape. Color map of 3D model corresponds to the deformation distance between this shape and the mean shape. Warm colors indicate shrinkage, cold colors indicate expansion with respect to the mean shape. Heatmaps are NOT to the same scale, as each effect scaled different. Dynamic visualizations of these effects can be found in the Supplemental Animations 1–3. (A) Skull centroid size: Increases in skull size expands the anterior brain case both vertically and laterally. (B) Sex: Sexual dimorphism is low and appears to map mainly on the basicranium. (C) Direction-of-cross: This effect shows offspring born to F1 hybrid mothers as having a higher neurocranium than those produced from pure A/J dams.