Fig. 1.

Morphometric analysis of New World monkey’s brain shape. (A) Ordination of 49 platyrrhine species in the morphospace defined by the first two principal components (PCs) of brain shape variation, which together account for ∼61% of total variance. Endocast at Left shows the measured landmarks (red), and curves (green) and surfaces (blue) semilandmarks on each individual (see also Fig. S6 and Table S2). Encephalization values (relative ECV) for each species are depicted by the color of each data point. Additionally, the three platyrrhine families are indicated, along with the genus Aotus, whose position in the platyrrhine tree is contentious. (B) Brain shape changes associated with the main axes of variation. Models were obtained by warping a surface model of the mean platyrrhine shape along PC1 and PC2 scores. See also Movies S1 and S2.