The nearly complete skull of a 95-million-year-old sauropod dinosaur named “Ann” found in western Queensland has unearthed new insights into how the massive creature lived.
Researchers found the skull belonged to the species Diamantinasaurus matildae, known for having small heads, long necks and tails, barrel-like bodies, and four columnar legs.
A Curtin University-lead research team has analysed Australia’s first nearly-complete sauropod dinosaur skull known as the Diamantinasaurus Matildae.(Supplied)
Stephen Poropat, lead researcher from Curtin University’s School of Earth and Planetary Sciences, said Ann is the first sauropod dinosaur found in Australia to include most of its skull, and the first Diamantinasaurus to have its back foot preserved.
“This skull gives us a rare glimpse into the anatomy of this enormous sauropod that lived in north-east Australia almost 100 million years ago,” Dr Poropat said.
“In analysing the remains, we found similarities between the ‘Ann’ skull and the skull of a titanosaur called Sarmientosaurus musacchioi, which lived in South America at about the same time as Diamantinasaurus lived in Queensland.
“These include details of the brain case, the bones forming the back end of the skull near the jaw joint, and in the shape of the teeth (which are conical and curved).”
Searching for greener pastures
Dr Poropat said his team’s research supported previous theories that sauropods were travelling between continents in search of more balmy weather.
“We suggest that sauropods were travelling between Australia and South America, via Antarctica, during the mid-Cretaceous. Warmer conditions that far south might have been favourable for them.
(From left) Suzanne Mcnestrie, Ruairidh Duncan, Stephen Poropat and Tim Ziegler take part in a CT scan of “Ann” at St Vincent’s Hospital, Melbourne.(Supplied: Adele Pentland)
“The window between 100 and 95 million years ago was one of the warmest in Earth’s geologically recent history, meaning that Antarctica, which was more or less where it is now, had no ice.
“Similarly, Australia, which was much further south than today, was warmer with less seasonality.
“In that climate, Antarctica was forested, and might have been an attractive habitat or pathway for wandering sauropods.”
He said the species was one of the latest dinosaurs to exist.
“Our research suggests that Diamantinasaurus was one of the most ‘primitive’ titanosaurs.
“Gaining a better understanding of this species might explain why titanosaurs were so successful, across so much of the world, right until the end of the Age of Dinosaurs.”
Predator or prey?
The Diamantinasaurus was around 20 metres long and weighed up to 25 tonnes.
“It would be able to peer into a two or three-storey building, it was about as heavy as four average African elephants and about as long as a tennis court,” Dr Poropat said.
But as a placid herbivore, it wouldn’t have been much cause for concern if you came across one in the wild.
“Being pursued by a sauropod would’ve been like being pursued by a turtle,” Dr Poropat said.
“They were not fast moving. They were not terribly brainy, and you look at their teeth, they’re not adapted for eating prey at all.”
A palaeontology paradise
Ann’s skull was found in 2018 on Elderslie Station, near Winton, by the Australian Age of Dinosaurs Museum during its annual dinosaur dig.
The Australian Age of Dinosaurs in Winton is drawing paleo-enthusiasts to outback Queensland.(ABC Western Queensland: Ellie Grounds)
It was the third fossil specimen of Diamantinasaurus matildae to be discovered on Elderslie by the museum and the fourth specimen overall.
In 2012, the fossils of “Ollie” were unearthed, the first juvenile sauropod to ever be found in Australia.
The excavation process found dozens of fossils, including thoracic vertebrae, ribs, a scapula, a humerus, a thumb claw and a femur.
In 2019, 17 curved teeth were found at the site, changing what researchers knew about how the sauropod would have smiled.
The sauropod’s teeth were found near Winton in 2019.(Supplied: Trish Sloan)
A “really unusual” discovery of dinosaur teeth in outback Queensland has changed what researchers know about how a 20-tonne titanosaur would have smiled.
New research on 17 curved teeth that were unearthed at a dig site near Winton in 2019 has shed light on sauropod Diamantinasaurus matildae’s role in its prehistoric ecosystem.
Australian Age of Dinosaurs museum research associate Stephen Poropat said previous descriptions of the Diamantinasaurus’ skull were modelled in part from a comparable titanosaur from Brazil.
“We’ve found dozens of sauropod skeletons in Winton over the past two decades, and this was the first one that preserved a lot of teeth which is really unusual,” Dr Poropat said.
The sauropod’s teeth were found near Winton in 2019.(Supplied: Trish Sloan)
“They are between 98 and 95 million years old, we haven’t got an exact date on them yet, but that’s the boundary that we’re working with at the moment.”
He said the teeth showed the dinosaur was probably feeding at least one metre above the ground, not really ingesting much soil or grit, and probably up to 10m above the ground.
“Imagine a three-storey building,” he said.
An artist’s impression of a Diamantinasaurus, a sauropod that once roamed what is now Queensland.(Supplied: Australian Age of Dinosaurs Museum)
Dinosaur dental important
The “robust and chunky” Diamantinasaurus teeth were a point of difference with other sauropods, which in general had more plentiful, narrower teeth suited for eating lower to the ground.
Stephen Poropat says fossils are the key to understanding how dinosaurs lived.(Supplied: Trish Sloan)
It was a valuable distinction to make, according to Dr Poropat, who has dedicated part of his career to understanding as much as possible about the titanosaur.
“The fossils that we’re finding are all a part of an ancient ecosystem that occupied central Queensland when it was much wetter and quite a bit warmer than it is today, despite the fact that Australia was much further south at that time,” Dr Poropat said.
“To be able to understand how many different species of sauropods were coexisting in this area, we need to be able to constrain what each of their diets was, and we can do that using their teeth.”
Digging up more
There is still much to learn about Diamantinasaurus matildae, which is in the running to become Queensland’s state fossil emblem.
Australian Age of Dinosaurs executive chairman David Elliott said almost two dozen of the titanosaur’s teeth had been found.
“We’ve got enough there, and enough bones from the site, that we can start to fit those teeth to the animal that owns the bones,” Mr Elliott said.
“That’s really exciting, because up until now we really haven’t had much of an idea what the Diamantinasaurus’ skull or shape of the face really looks like.”
Diamantinasaurus teeth were unearthed near Winton in 2019.(Supplied: Trish Sloan)
Dr Poropat said the future was bright for the sauropod.
“The good thing is, we do have more specimens of Diamantinasaurus in the pipeline that are going to make our understanding of this animal even clearer in the future,” Dr Poropat said.
“We keep digging more up each year.”