Figure 4.

Rates of femur and forelimb evolution in theropod dinosaurs and early birds. Branch lengths are scaled, with the red branch leading from the centre to the Paraves indicating a 200-fold, and the yellow branches (upper left) to Microraptorinae indicating an eightfold, increase in rate of evolution relative to the background rate. The time-calibrated phylogeny is shown in dark grey, and circular rings indicate 5 Myr time intervals from the K–Pg boundary. Silhouettes drawn by Scott Hartman, Matt Martyniuk, Emily Willoughby, Jaime Headon and Craig Dylke, or modified by T. Michael Keesey, were downloaded from http://phylopic.org. From [56]. (Online version in colour.)