Unique tooth gave T Rex that bone-crunching bite

But new research, published Tuesday in the journal Scientific Reports, proposes another explanation for those structures – that they were present in teeth before they even erupted from dinosaurs’ gums, and that they played a key role in maintaining the fearsome, knife-like serrated edge of the animals’ bite.

These creatures first appeared about 200 million years ago and were the dominant terrestrial meat-eaters until the age of dinosaurs ended about 65 million years ago.

Scientists knew about the unusual tissue structures inside theropod teeth before this study, but hadn’t been able to determine if the structures were caused by stress on the teeth, Brink said. Theropods include Tyrannosaurus Rex, turkey-sized Compsognathus longipes, and the agile Velociraptor.

ONLY one reptile living today has the same kind of tooth structure – the three-metre long Komodo dragon from Indonesia.

While other extinct animals had teeth that were superficially similar, it was the special arrangement of tissues inside the tooth that strengthened and improved the function of T. rex teeth.

The researchers also discovered that the unique arrangement of tooth tissues didn’t develop in response to these carnivores chewing hard materials.

[Why paleontologists love the noisy, featherless, inaccurate dinosaurs of “Jurassic Park”].

The dinosaur – dubbed Zhenyuanlong suni by researchers – grew to more than five feet in length, and had very short wings compared with other dinosaurs in the same family, consisting of multiple layers of large feathers.

Its teeth have been found embedded in the bones of its prey and chunks of bone appear in its fossilised dung, says the study’s lead author palaeontologist Kirstin Brink of the University of Toronto Mississauga.

This latest discovery suggests that winged dinosaurs with larger and more complex feathers were more diverse than previously thought.

“In theropods, the serrations are larger and deeper than the superficial view suggests, making them stronger and longer lasting, less likely to get damaged or worn”, University of Toronto Mississauga paleontology professor Robert Reisz said.

The problem was that it took a while for a tooth to replace itself.

Imaging analysis of theropod teeth reveal a penetrating saw-like structure that allowed T. rex and Allosaurus, as well as earlier theropods like Coelophysis, to slash through thick animal skin and bone.

“Therefore, having specially reinforced teeth means less tooth breakage and less gaps in the jaw, leading to more efficient eating”.

“I sectioned teeth from eight other theropods besides Albertosaurus, and found that the structure is actually in all theropods, and it’s not actually a crack”, said postdoctoral researcher Kirstin Brink in a Live Science interview.