Dinosaur locomotion from a new trackway.

Ardley Quarry in Oxfordshire, UK, contains one of the most extensive dinosaur-trackway sites in the world, with individual trackways extending for up to 180 metres. We have discovered a unique dual-gauge trackway from a bipedal theropod dinosaur from the Middle Jurassic in this locality, which indicates that these large theropods were able to run and that they used different hindlimb postures for walking and running. Our findings have implications for the biomechanics and evolution of theropod locomotion.