Dr Roger Benson, from Cambridge University, who identified the fossil, said: ”This is an exciting discovery because tyrannosaur fossils had only ever been found in the northern hemisphere before and some scientists thought tyrannosaurs never made it down south.
”Although we only have one bone, it shows that 110 million years ago small tyrannosaurs like ours might have been found worldwide. This find has major significance for our knowledge of how this group of dinosaurs evolved.”
During the 200 million-year-reign of the dinosaurs, the Earth’s continents were still emerging from what began as a single land mass.
The Australian tyrannosaur, dating back 110 million years, hails from the middle stages of the continental break-up.
South America, Antarctica, Africa and Australia had separated from the northern continents but not yet parted from each other.
The 30 centimetre-long fossil, found at Dinosaur Cove in Victoria, belonged to a much smaller cousin of T. rex.
Currently known only by its code-name, NMV P186069, the creature was 10 feet long and weighed around 12 stone.
Like its giant 40-foot, four tonne ”big brother” it would have had a large head and distinctive small arms.