Organisms Commons^™

Decoupling Body Shape And Mass Distribution In Birds And Their Dinosaurian Ancestors, Sophie Macaulay, Tatjana Hoehfurtner, Samuel R.R. Cross, Ryan D. Marek, John R. Hutchinson, Emma R. Schachner, Alice E. Maher, Karl T. Bates

School of Medicine Faculty Publications

It is accepted that non-avian theropod dinosaurs, with their long muscular tails and small forelimbs, had a centre-of-mass close to the hip, while extant birds, with their reduced tails and enlarged wings have their mass centred more cranially. Transition between these states is considered crucial to two key innovations in the avian locomotor system: crouched bipedalism and powered flight. Here we use image-based models to challenge this dichotomy. Rather than a phylogenetic distinction between ‘dinosaurian’ and ‘avian’ conditions, we find terrestrial versus volant taxa occupy distinct regions of centre-of-mass morphospace consistent with the disparate demands of terrestrial bipedalism and flight. …