The plant-eating Eocursor lived about 220 million years ago, during the Triassic period and was about the size of a fox. It had two long legs and was likely to be a fast runner that could outrun predators and this is how it gets his name, Eocursor parvus means ‘early little runner’. The exciting thing about this discovery is that the Eocursor provides a missing link between the slower, larger, ‘bird-hipped’ herbivores of the later Jurassic and Cretaceous periods and earlier plant eaters. 

As a result of this find a new evolutionary tree has been drawn up showing how primitive ornithischians (bird-hipped dinosaurs) are related to each other. The tree shows how Eocursor is one of the most primitive known ornithischians and it also shows how ornithiscians spread throughout the world later than scientists previously thought. Ornithischians that developed late than the Eocursor are the larger and slower Stegosaurus and Triceratops.