Fig. 8
From: The relationship between sternum variation and mode of locomotion in birds
Sternal shape deformations showing the independent effects of forelimb propulsion and aerial flight. 3D models in grey are warped from the Ramphastos ambiguus sternum according to the algorithm indicated by the point- and line-clouds to the bottom-right of each 3D model. Forelimb propulsion is associated with a longer sternal body and shallower, cranially projected keel; aerial flight is associated with a shorter sternal body, a deeper, rounded keel, and rounded lateral trabeculae.