We now know dinosaurs as the huge reptiles who dominated the Earth, but scientists have long-wondered why it took them 30 million years to reach apex status. A new study of their fossilised poop and vomit may have found the answer. Well, the food found within their poop and vomit.
According to the research, carnivore dinosaurs like the T.rex may need to thank their herbivore predecessors for their huge size. If these plant-eaters hadn’t bulked up on flora, researchers suggest dinosaurs may not have evolved into the gigantic creatures they came to be.
The fossilised poop and vomit (known slightly more glamorously to scientists as bromalites or copralites) was dated around 230 to 200 million years ago – that’s about 100 million years before the reign of the T.rex, and 150 million years before the the dino-ending Chicxulub asteroid hit our planet.
From the undigested meals of the early dinos, scientists pieced together a ‘food web’ over time. This essentially showed who ate who throughout the Triassic period – and how the food chain evolved. They scanned over 500 fossils and found everything from beetles to bones and even half-digested fish in the fossils.
When researchers combined this information with climate data and other fossils, it gave them a perspective on what animals and insects may have been roaming the Earth alongside the dinos.
“Sometimes, seemingly unremarkable fossils contain remarkable information that can’t be found elsewhere,” Dr Martin Qvarnström, co-author of the study and researcher at Sweden’s Uppsala University, told BBC Science Focus.
Dr Grzegorz Niedźwiedzki, co-author of the study and also a researcher at Uppsala University, added: “Understanding the diet of early dinosaurs may help us understand why this group was so successful. A lot of the evolution of life on Earth has revolved around who ate whom and whether they were efficient predators or plant grazers.”
In the study, published in the journal Nature, researchers scanned digestive material samples from south-central Poland. In the late Triassic Period, this would have been in the northern part of the Pangaea supercontinent.
Around this time, experts believe there was a boost in volcanic activity and humidity, leading more moisture-loving plants to grow.
The study’s biggest finds were achieved using scanning technology to see intricate details in the fossils.
“The 3D imaging we employed works much like a CT scanner at a hospital, with the difference that the energy in the X-rays is a thousand times higher,” Qvarnström explained.
These fossils have allowed scientists to hypothesise why it took tens millions of years for dinosaurs to take over – by using them to analyse how populations of vertebrates changed in physical size, and prevalence during this period.
They hope to use this research model to study ancient species from other parts of the world.
“I hope we can convince our colleagues that coprolites are not just material for good jokes but also highly interesting for reconstructing ancient food webs,” Qvarnström said.
According to Niedźwiedzki, “Everyone hunts for fossilised skeletons, but it is the coprolites that tell the most about the dramas from millions of years ago.”
About our experts:
Dr Martin Qvarnström is a researcher at the Uppsala University in Sweden. His research focuses on how fossils can reveal the diet of reptiles like the dinosaurs.
Dr Grzegorz Niedźwiedzki is also a researcher at Uppsala University. He focuses on the early evolution of dinosaurs and other tetrapods.
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