Not content with announcing Australia’s largest dinosaur find, palaeontologists are already looking ahead to future finds, including an ancient apex predator that would have eaten it for dinner.
“There is a very large predatory dinosaur out there somewhere,” Queensland Museum palaeontologist Scott Hocknull says. “We just haven’t found it yet.”
Australia’s largest discovered dinosaur, “Cooper”, took the world by storm this week, but the palaeontologists who found him say that despite his great size he is just the tip of a fossil iceberg beginning to be unearthed.
Cooper, a massive long-necked plant-eating sauropod dinosaur officially named Australotitan cooperensis in a scientific paper published this week, was discovered in the area around Cooper Creek near the town of Eromanga in south-west Queensland.
The specific fossils were first unearthed in 2007, and it has taken since then to painstakingly unearth the whole skeleton, examine it and publish the scientific paper formally naming the giant animal.
The discovery of Cooper in the earth of the Eromanga basin has scientists daring to hope — could Australia’s largest carnivorous dinosaur also be out there, one excavation away from stalking out of the ancient landscape?
Titanosaurs such as Cooper are among the largest creatures to have ever lived, with Cooper standing over six metres, or two storeys, tall and as long as a basketball court.
There were titanosaurs on other continents, in particular South America, which has yielded several species even larger than Cooper.
Hocknull says that is exciting, because what was also found on those continents were giant meat-eating dinosaurs much larger than Tyrannosaurus rex.
“In South America, there are gigantic theropod dinosaurs like giganotosaurus, from Africa there’s carcharodontosaurus, we find these very large meat-eating dinosaurs everywhere, but we haven’t found them [in Australia],” Hocknull says.
Of the carnivorous dinosaurs discovered in Australia so far the largest is Australovenator wintonensis, which was discovered in the more well-known fossil fields around Winton, some 660 kilometres north of Eromanga.
It grew to around two metres tall and six metres long, and would likely have preyed on the smaller sauropods found in that area, but Hocknull says it was unlikely to have given Cooper and his kind much trouble.
There are usually far fewer predators than prey in ecosystems around the world, and the fossil record shows dinosaurs were no exception.
“They’re probably few and far between on the ground, for every 50 sauropods you’ll find one meat-eating dinosaur, so we’ve got to find a few more sauropods,” Hocknull says.
Researchers have certainly been doing that.
While Cooper was the first dinosaur found in the Eromanga region, it is far from the last, with dozens of specimens fully or partially unearthed in the years since.
Noteworthy finds have been Zac, believed to be from the same species as Cooper but far more complete, with some portions of the skeleton even still fully or partially articulated, and George, which is much more fragmentary but could be even bigger than Cooper.
Eromanga Natural History Museum director Robyn Mackenzie says they have been hard at work since she and her husband, Stuart, first stumbled across the bones on their cattle property.
“To be perfectly honest, I think we would have been very happy with just that piece of bone at that point in time. But of course we went back to that site and found a lot more, and it’s just grown from there,” she says.
The Mackenzies founded the museum specifically to manage and display the wealth of fossils they had stumbled across, and along with a number of local volunteers partnered with experts from the Queensland Museum to go through the laborious process of digging up the massive bones.
Far from chipping away with tiny hammers and brushes, they often needed large-scale earthmovers to shift the dirt and big cranes and flatbed trucks to take away the fossils, some of which weigh hundreds of kilos by themselves.
Since their initial discovery more than 80 sites have now been identified in the area, and Mackenzie says that is still only scratching the surface of what they believe is out there.
“These discoveries are a really important part of our dinosaur fossil history, the book is only just starting to be written, these discoveries are the tip of the iceberg in terms of what we’re finding down here and what they’re finding across Australia as well,” she says.
Major Eromanga Fossil Finds After “Cooper”
- “George” – possibly Australotitan cooperensis. Fragmentary but much larger than Cooper with femur measuring 2.2m vs Cooper’s 1.9m
- “Tom” – a single femur, humerus and toe bone all from a small individual, likely Australotitan cooperensis
- “Syd” – likely A. cooperensis but only represented by vertebrate and teeth. It had been squashed into the mud within the 100m long trample zone preserved near the Cooper skeleton.
- “Sandy” – likely A. cooperensis but only known from a single ulna – the first relatively complete bone found in the area in 2005.
- “Zac” – likely A. cooperensis. The most complete sauropod skeleton found in Eromanga and possibly Australia. Smaller than Cooper but better preserved.
- “Monty” – possibly A. cooperensis. A very large sauropod, possibly larger than “George” but few bones have been prepared.
Western Queensland was first identified as a major site for fossils over 20 years ago, but up until now much of the activity has been around Winton.
An annual dig is held in the area every year (with a break in 2020 due to the pandemic) and thousands of fossils have now been uncovered of everything from large dinosaurs to ancient crabs and plants — not unusual for the Cretaceous time period over 90 million years ago, when the area was the marshy shore of a great inland sea.
However, the area around Winton itself is just a small part of what has come to be called the “Winton formation” — a geological area stretching all the way to Eromanga in the south, hundreds of kilometres away.
“The whole area is this great flat plain with a ring of mountains around it that was pushed up to the surface about 40 million years ago,” Mackenzie says. “I think of it like this giant pothole to the past.”
Eromanga has been preparing for an explosion of interest in the wake of the Cooper announcement, but the Mackenzies admit it has been stressful waiting dozens of years for word of their work to finally hit the mainstream.
“It’s quite extraordinary what it’s come to,” says Stuart Mackenzie, who is also Quilpie Shire’s mayor.
“All the work, the decades of prep — this is a project that will outlive us and hopefully build its own momentum.”
Says Robyn Mackenzie: “There’s nothing quite like walking up to a dinosaur site and seeing all this bone on the surface and not having a clue what type of animal it is.
“Then you look closer, pick up bits of bones and start figuring it out.”