Figure 4: Results of a principal components analysis calculated
with the variance and covariance estimates for 18 craniofacial traits
for the Caribbean, SSI generalist-only, and SSI radiating populations.PC1 and PC2 explain 59% and 16% of the variance, respectively. Shapes
and colors indicate the three focal groups (dark grey triangle:
Caribbean group, light grey square: SSI generalist-only group,
gold circle: SSI radiating group), and ellipses represent 95%
confidence intervals per group. Arrows display four craniofacial traits
that are most strongly correlated with PC1 (jaw closing in-lever and
lower jaw length) and PC2 (maxillary head protrusion and nasal tissue
protrusion). San Salvador Island generalist-only group clusters
separately from the Caribbean and San Salvador Island radiating groups
along PC1.