A 3m-long dinosaur fossil from China which predates T. rex by 60 million years is a blueprint for the mighty carnivore, say researchers.

They tell Science magazine that the fossil displays the same features as T. rex but in miniature.

The new species, Raptorex kriegsteini, would have weighed around 65kg; its descendants were 90 times as massive.

Scientists believe it could be the "missing link" between earlier species of dinosaur and T. rex.

The 125-million-year-old specimen suggests that T. rex's characteristic big head with enhanced jaw, relatively small forearms and huge back legs were inherited from this much smaller dinosaur, and that the body type changed little over millions of years except in size.