Abstract
A central research program in evolutionary biology over the past 50 years has involved interpreting macroevolutionary patterns, such as key innovation and preadaptation, as mediated by interactions between single phenotypic traits and shifting ecological landscapes. While this focus has generated substantial evidence for the potency of environmental pressures in driving evolutionary changes, it has also created conceptual frustrations. I present analyses of a character matrix sampled across the haplorrhine skeleton that revealed several suites of integrated characters displaying distinct patterns in macroevolutionary disparity throughout the Miocene. Comparison of these patterns to those in neurological development revealed general support for a pattern in evolutionary and developmental flexibility shared by all great apes. Shifting and reduced constraint in apes was met with episodic bursts in phenotypic innovation that built a wide array of functional diversity over a foundation of shared developmental and anatomical structure that was laid throughout the Miocene. Notably, both apes’ exceptional morphological disparity and humans’ phenotypic distinctiveness can both be explained by earlier shifts in integration. These patterns demonstrate that relaxation of integration can correspond to enhanced evolvability that has a ‘preadaptive’ effect by catalyzing later episodes of dramatic morphological remodeling.
Data archived online https://figshare.com/articles/parins-fukuchi_supp_zip/8063726
Footnotes
Major edits to text. Addition of two new analyses.