A Tyrannosaurus tooth embedded in dinosaur skull tells a violent story

First discovered 20 years ago, the rare fossil combo reveals a Cretaceous meal in the making. The post A Tyrannosaurus tooth embedded in dinosaur skull tells a violent story appeared first on Popular...

A rare dinosaur fossil on display at the Museum of the Rockies in Bozeman, Montana, tells a gory story. The skull from a large plant-eating Edmontosaurus has a tooth lodged into it, indicating that it may have met its final moments as a meal. The tooth in question belongs to one of the most famous dinosaurs on earth—Tyrannosaurus.

Montana was once home to Tyrannosaurus rex, the most famous of several known members of the fearsome Tyrannosauridae family. This apex predator stomped around until the end of the Age of Dinosaurs, roughly 66 million years ago. It lived alongside large plant-eaters like Triceratops and the duck-billed Edmontosaurus.

In 2005, paleontologists found a nearly complete Edmontosaurus skull in the fossil-rich Hell Creek Formation in eastern Montana. Now on display at the museum, a reexamination of the skull revealed one striking detail: a Tyrannosaurus tooth stuck inside its face. The findings are detailed in a study published today in the journal PeerJ.

a dinosaur skull — The full *Edmontosaurus* skull. The triangle indicates where the tooth is embedded. *Image: Montana State University/Museum of the Rockies.*

“Although bite marks on bones are relatively common, finding an embedded tooth is extremely rare,” Taia Wyenberg-Henzler, a study co-author and University of Alberta doctoral student, said in a statement. “The great thing about an embedded tooth, particularly in a skull, is it gives you the identity of not only who was bitten but also who did the biting. This allowed us to paint a picture of what happened to this Edmontosaurus, kind of like Cretaceous crime scene investigators.”

When comparing the embedded tooth to all of the known prehistoric inhabitants in the Hell Creek Formation, they found that it closely matched teeth of Tyrannosaurus. CT scans of the skull helped the team discover more details about the wound.

“A fossil like this is extra exciting because it captures a behavior: a tyrannosaur biting into this duckbill’s face,” added co-author and Museum of the Rockies’ Curator of Paleontology John Scannella. “The skull shows no signs of healing around the tyrannosaur tooth, so it may have already been dead when it was bitten, or it may be dead because it was bitten.”

a tooth loged in a skull — The *Tyrannosaurus* tooth. *Image: Montana State University/Museum of the Rockies.*

Tyrannosaurus was one of the largest carnivores to ever walk the Earth and paleontologists have been studying their feeding habits for decades. The tooth found inside this Edmontosaurus skull gives another look into Tyrannosaurus behavior. According to the team, the way that the tooth is embedded in Edmontosaurus’ nose suggests that the duck-billed dino met its toothy attacker face-to-face. Typically, this happens to an animal that is ultimately killed by a predator.

“The amount of force necessary for a tooth to have become broken off in bone also points to the use of deadly force,” said Wyenberg-Henzler. “For me, this paints a terrifying picture of the last moments of this Edmontosaurus.”