A new study has shed light onto the ability of dinosaurs to kill their prey: their serrated (having saw-like cutting edges) teeth allowed them to cut through flesh and bones better – specially those of other dinosaurs they fed on – and the very arrangement of the tissues within each of those teeth provided further strength and enhanced function. The findings have been published in the journal Scientific Reports.
A Gorgosaurus, armed with its specialised teeth, feeding on a young Corythosaurus 75 million years ago. Photo credits: Danielle Dufault.
Decades ago, when the unusual cracks embedded into the teeth of a predatory dinosaur were discovered, scientists thought they were the result of stresses caused by feeding. The teeth of other predators like the Tyrannosaurus rex and Gorgosaurus (both belonging to the group called theropods) also bore similar “cracks”. Recently, though, a team of scientists have revealed that the observed structure is not actually random.
The teeth of 8 other theropods have been examined with a scanning electron microscope and a synchrotron to delve into the physical and chemical structures. Mature and erupted teeth as well as immature and unerupted ones were analysed. The latter ones had not emerged from gums yet and, therefore, could not have suffered from the wear and tear of feeding.
The in-depth analysis showed that the cracks were not cracks at all. Rather, they were deep folds within the teeth that served as added strength for each serration, as protection against breakage, while also enhancing function. They are called deep interdental folds. The latter also have layers of calcified tissue (dentine) beneath the enamel coating providing further strength.
“We proposed a developmental hypothesis that these are structures created when the tooth is first forming,” said the lead author, Kirstin Brink, in a statement to Live Science. “It actually helps to deepen the serration within the tooth and strengthen each serration and the tooth overall.”
Thin section through a tooth of Gorgosaurus, from Alberta. Image credits: Danielle Dufault.
Furthermore, this feature might be unique to theropods. Thanks to these minor details, theropods were successful predators millions of years ago.
“What is so fascinating to me is that all animal teeth are made from the same building blocks, but the way the blocks fit together to form the structure of the tooth greatly affects how that animal processes food,” Brink said in a statement. “The hidden complexity of the tooth structure in theropods suggests that they were more efficient at handling prey than previously thought, likely contributing to their success.”