Forelimb posture in dinosaurs and the evolution of the avian flapping flight-stroke

A new approach using Strouhal number is used for gaining insight into the forelimb posture in dinosaurs and early stages of flight evolution, in the absence of a living analogue. The calculations have shown that even moderate wing movements are sufficient for generating rudimentary thrust and that a propulsive flapping flight-stroke is evolved via gradual incremental changes in wing movement and wing morphology.