Bones from the largest theropod dinosaur ever discovered in Australia have been uncovered in western Queensland.
Key points:
- Theropods could be up to 2 metres high and 7 metres long
- The latest discovery closely resembles a species found nearby in 2006
- It had large hands with what Dr White called "recurved claws"
They were initially uncovered in 2017 at the now world-famous dinosaur fossil field in Winton, but were only recently identified as most likely belonging to the Australovenator wintonensis species, discovered in 2006.
Lead researcher Dr Matt White from the University of New England said when the bones were first uncovered "they didn't look like much at all".
"We had a really good look through all of the fragments and that's when I got quite excited because we started to find the distal elements of bones that resembled a theropod, which are extremely rare," he said.
Theropods are a large group of bipedal and largely carnivorous dinosaurs, including the Velociraptor and Tyrannosaurus rex.
The bones cannot be definitively identified to a species, but closely resemble an Australovenator wintonensis specimen found less than 2 kilometres away in 2006.
Dr White said the dinosaurs could be up to 2 metres high, between 5 to 7 metres long, and were similar in appearance to the velociraptors depicted in the film Jurassic Park.
"Except the claws are on the hands, not the feet," he said.
"It had quite large hands, but on each hand it had two recurved claws that were quite large … and like birds you have a horny sheath over the top so they would have ended up round about close to 25 to 30 centimetres."
Hunter or scavenger?
Dr White said while it was hard to determine a dinosaur's hunting behaviour based on its skeleton, Australovenator was probably some kind of predator.
He said it had two claws on each hand "used for grappling prey".
Dr White said they may also have done some scavenging.
"If they've got an easy feed, they probably would have had an easy feed."
He said there were almost certainly many of them hunting the same prey.
"Given the amount of teeth we've found [it is] probably not just one feasting on a carcass, it would have been two or three."
Dr White said sauropods — long-necked, quadrupedal herbivores — were almost certainly Australovenator's main prey.
"Every sauropod site that we have dug in over the years, we find these isolated shed teeth," he said.
"We haven't really found teeth that are much bigger than Australovenator, so these things would have been the top carnivore.
"We just haven't found any other evidence of anything larger than these guys, Australia-wide."
Did dinosaurs have feathers?
Dr White said whether this group of dinosaurs had feathers was still hotly debated among members of the scientific community.
"There's two major groups [of theropods] — you've got your more primitive Tetanurans where Allosaurus is, and then have your Coelurosaurs where you have Tyrannosaurus."
He said the Tyrannosaurus was a member of the group that probably had feathers.
"I suspect it is within the more primitive group, but it is still heavily debated."
Dr White said this was one of the reasons each new dinosaur find was important, because it brought scientists closer to answering such questions.
"We can start to work out, well — did they have feathers? Which group they sat in, and unfortunately the preservation out at Winton is not good enough to preserve feathers."
The newly identified theropod bones are on display at the Australian Age of Dinosaurs Museum near Winton.
Australoventors fed on larger herbivores.(Travis Tischler)
