FIG. 2 in Pennaraptoran Theropod Dinosaurs Past Progress And New Frontiers

FIG. 2. Three axes scatterplot of a functional landscape of Theropoda flight capability as estimated by logged body mass, pectoral muscle mass, and wing area. The surface is a smoothed regression through all the points. The surface has a discrete ridge on which extant volant birds lie on whereas all nonavialan theropods plot on its slope.