Fig. 3.

Phylomorphospace of PCA values on skull shape variation based on species means, using the R package geomorph. Each clade is depicted with a different shape, while burrowing behavior is indicated by different colouring. The two main different diet types (specialist and generalist) are also indicated by a schematic of each type and background colouring. Thin-plate spline (TPS) deformation grids are displayed to indicate extreme variation on skull shape among different species (names in bold), and only species from the outer limits of the morphospace are depicted