Human face-off: a new method for mapping evolutionary rates on three-dimensional digital models

Modern phylogenetic comparative methods allow estimating evolutionary rates of phenotypic change, how these rates differ across clades, and assessing whether the rate remained constant over time. Unfortunately, currently available phylogenetic comparative tools express the rate in terms of a scalar dimension, hence they do not allow us to determine rate variations among different parts of a single, complex phenotype, or charting of realized rate variation directly onto the phenotype. Herein, we present a new method which allows the mapping of evolutionary rate variation directly on three-dimensional phenotypes, informing on the direction and magnitude of trait change automatically.

This new method, implemented by the function rate.map embedded in the R package ‘RRphylo’, is based on phylogenetic ridge regression rate estimates. Since the latter represent ridge regression slopes, they possess sign and magnitude. In ‘RRphylo’, different rates are calculated for different districts of t...