'Dawn runner' casts light on birth of the dinosaur

Eodromaeus needed some opportunity, some change of events to get the upper hand, so it was extinctions of other animals that were already there which ultimately gave dinosaurs their foot in the door about 200 million years ago."
Dr Paul Barrett, research scientist with the Natural History Museum, said the research was "very interesting" and could bring us closer to the first dinosaur, which he thinks must have lived very shortly before Eodromaeus.
"We have ideas of what dinosaurs looked like from later members of the groups but they're likely to look more similar as they get closer to that ancestral dinosaur," he said.
These two dinosaurs, he said, could represent two of three great dinosaur lineages - the theropods and the sauropods - the other being the ornithischia group to which creatures such as Stegosaurus and Triceratops belonged.