Scientists discovered ferocious dinosaurs such as the Tyrannosaurus rex owe their hunting success to a deeply serrated tooth that allowed it to easily slice through flesh and even bone.
A team of researchers determined the saw-like tooth was unique to carnivorous theropods such as T. rex and Allosaurus, the University of Toronto reported. Other animals that walked the Earth at that time had teeth of a similar structure, but only the meat-eating group had an observed special arrangement of tissues inside the tooth that improved its strength. The only creature alive today that has the same superficial tooth structure is the Indonesian Komodo dragon.
"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," said Kirstin Brink, a post-doctoral researcher in the Department of Biology at UTM. "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."
The scientists were surprised to find the arrangement of tooth tissues did not develop in response to the animals chewing on hard material because the animals grew new teeth throughout their lifetime in the same way was modern-day reptiles. To make their findings, the researchers used a scanning electron microscope to analyze the chemical composition of tooth slices from eight carnivorous theropods.
"What is startling and amazing about this work is that Kirstin was able to take teeth with these steak knife-like serrations and find a way to make cuts to obtain sections along the cutting edge of these teeth," said professor Robert Reisz of the Department of Biology and the UTM vice-principal of graduate studies. "If you don't cut them right, you don't get the information. This brought about a developmental explanation for the tooth formation; the serrations are even more spectacular and permanent."
The findings were published in a recent edition of the journal Scientific Reports.
