Fig. 3

Shape variation for each cranial module. Exploded view of positive (+) and negative (−) shape extremes for each cranial module along PC1 (see Fig. 1 for module definitions). Siphonops annulatus is also presented in lateral (left) and ventral (right) aspect, with the landmarks and semilandmarks coloured by module. Extreme shapes were generated from individual module PCAs, so PC axes do not align and direction is arbitrary. All modules are presented in one view, except the maxillopalatine module (two views). Aspect of modules is consistent with cranial aspect, except for the occipital (posterior view) and the parietal and frontal (dorsal view). Specimens lacking a pterygoid or stapes module were removed from these PCAs, for visualisation purposes only