Two pterosaur fossils dating back 107 million years have been confirmed as the oldest found in Australia. The finds are “another piece of the puzzle” in understanding these extinct giant flying reptiles.
The bones were first discovered in Dinosaur Cove in Victoria in the late 1980s.
One of the bones is a partial pelvis belonging to a pterosaur with a wingspan of more than two metres. The other is a small wing bone belonging to the first juvenile pterosaur reported in Australia – this individual would have had a wingspan of about one metre.
Pterosaurs were not dinosaurs, but lived alongside them during the Mesozoic, known as the “Age of Dinosaurs”, between 252 and 66 million years ago.
These giant flying reptiles were found around the world. They include species as small as pigeons, to the largest animals to ever have flown – the Quetzalcoatlus, which would have stood as tall as a giraffe (about five metres) and had a wingspan the size of a small biplane plane (about 11-12 metres).
All pterosaurs became extinct at the end of the Mesozoic.
Lead researcher on the Dinosaur Cove fossils, Adele Pentland, a PhD candidate at Curtin University in Western Australia, told Cosmos that pterosaurs were the first vertebrates to develop powered flight.
“During the Early Cretaceous, the most common types of pterosaurs that we have are pteradactyloid pterosaurs, or short tailed pterosaurs,” Pentland says. “It’s hard to say whether these individuals had edentulous [toothless] beaks or if they had jaws filled with teeth because we only have two isolated bones. That’s part of the reason why I didn’t name a new species as well.”
Despite not being able to confidently name a new species, Pentland says the marked size difference between the bones suggests two different individuals, including Australia’s first reported juvenile pterosaur.
Pentland says that pterosaur fossils are hard to come by, especially in regions that used to be in the polar circles like Victoria.
“What’s interesting to me is the site where these bones came from. During the Cretaceous [145-66 million years ago], Australia was part of the big southern supercontinent Gondwana. This part of Australia was much further south than it is today. It was within the polar circle. It wasn’t locked in ice, but there were weeks, if not months, of continuous darkness. Yet we have this small, young pterosaur at this site.
“Previous research indicates that from a young age, pterosaurs were able to fly pretty well. We’re getting a little bit closer to addressing the question: were polar pterosaurs permanent year-round residents or were they migratory? Until we find eggs, or newly hatched pterosaurs, unfortunately, my research won’t address that question. But hopefully, we can sort of use this to spur on some more excavations along these sites and find the right fossils,” Pentland remarks.
“It will only be a matter of time until we are able to determine whether pterosaurs migrated north during the harsh winters to breed, or whether they adapted to polar conditions,” Pentland says. “Finding the answer to this question will help researchers better understand these mysterious flying reptiles.”
Pentland explains that the Early Cretaceous landscape in south-eastern Australia would have been very different from today.
“There were temperate forests filled with conifers, ferns, ginkgoes, maybe a few angiosperms [flowering plants] kicking around, but not too many,” she explains.
Other animals include tiny early mammals, small herbivorous ornithopod dinosaurs, freshwater plesiosaurs, and the area’s top predator – the six-metre-long theropod dinosaur Australovenator.
While only a few million years older than the previous oldest pterosaur fossils recorded in Australia, Pentland is hopeful that future digs will unearth even older pterosaur bones that can give a broader understanding of the ancient flying reptiles on the continent.
“Unfortunately, in Australia we don’t have a lot of surface exposures of Jurassic and Triassic rock. There’s some Triassic stuff down in Tasmania. So, up until this point, all of the Australian pterosaur fossils have been Cretaceous in age.”
The research is published in the journal Historical Biology.
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