They might be yellowed and stained but as far as dinosaur teeth go, the 17 choppers unearthed by scientists in Australia’s outback Queensland are something to smile about.
The fossilised teeth come from a group of dinosaurs known as sauropods, giant, plant-eating, four-legged creatures that lived millions of years ago in an area around modern-day Winton in Western Queensland.
The area around Winton has become world famous as a repository of hugely significant fossils from flora and fauna that roamed the wilds of Gondwanaland, as scientists now call the mega continent that preceded contemporary Australia.
The fossil rich fields where these teeth were found were once the shore of an incredibly vast inland sea that teemed with an astounding variety of ancient life.
The teeth all come from a species of dinosaur known as the engagingly named Diamantinasaurus, a creature that lived in the area during the late Cretaceous period roughly 94 million years ago where they grew to about 16 metres in length and weighed as much as 20 tonnes.
Dr Stephen Poropat, from Australia’s Swinburne University of Technology, says the teeth are hugely significant in helping us understand more about the behaviour of these incredible creatures.
“These teeth are helping us put the smiles back on dinosaurs,” he quipped. “They can give you so much information about the diet of the animal. Like all sauropods it was likely stripping plants with these peg-like teeth, and we saw wear patterns consistent with that.
“But what was really interesting was that we didn’t see any micro-wear patterns as we sometimes see on smaller sauropods.”
What that means, he says, is that larger sauropods such as the Diamantinasaurus were almost certainly grazing on plants that were up off the ground – somewhere between one and 10 metres high in fact – and suggests they occupied an ecological niche that sat alongside other smaller dinosaurs that survived on ground plants.
“These sauropods were unlike any animal that lives on earth today,” Dr Poropat says. “To understand their place in the ecosystems that they inhabited is really important.”
The teeth from the Winton Formation were all remarkably similar –conical, then curved and pointed at the end and perfect form for trimming plants.
“Then they would use what was presumably a pretty long and muscular tongue […] to then pull the food straight down the gullet,” says Dr Poropat.
“Once they had swallowed their food – no processing in the mouth at all, no chewing – they would pass it through to the rest of the digestive system. And it would basically act as giant fermenting vats. They may have kept these meals inside their bodies for up to two weeks before excreting.”
The teeth were found by panlentologists in 2019 and 2021 at a site known as “Mitchell” on a sheep station about 60 kilometres west of Winton. Other tooth fragments were found on another site known as “Matilda” and yet another on a site designated as “Alex” site, 60km northeast of Winton.
The scientists made casts of the teeth which were coated in a very thin layer of gold, enabling them to be scanned using an electron microscope for further study. Even more teeth has since been discovered in the area.