Figure 3.

Evolutionary rate analysis of Early Cretaceous birds using the ‘equal’ method and a root length of 2 Ma. (a) Result of branch likelihood test for the first most parsimonious tree where branches are not treated separately; (b) result of branch likelihood test for the same tree where terminal and internal branches are treated separately. See electronic supplementary material, figure S5, for the same analysis where the Late Cretaceous birds are included. For all plots, the colour scheme repeats that of figure 2. (Online version in colour.)