American scientists say they have discovered the remains of a dinosaur, thought to be the ancestor of Tyrannosaurus Rex.
Both species are almost identical in structure, but the new dinosaur is nearly a hundred times smaller and is thought to have lived 60 million years earlier than T-rex.
The remains had been found in north-eastern China, from where they were smuggled out of the country and offered for sale.
Paul Sereno from the University of Chicago examined the fossil of the dinosaur and told the BBC what made it so extraordinary: "It's as close to the proverbial missing link on a lineage as we might ever get for T. rex.
"From the teeth to the enlarged jaw muscles, the enlarged head, the small forelimbs, the lanky, running, long hind-limbs with the compressed foot for hunting prey: we see this all, to our great surprise, in an animal that is basically the body weight of a human or 1/90th the size that ultimately this lineage would reach in T. rex at the end of the Cretaceous."