Research Communications

Scientists discover rare, wounded dinosaur in Utah 

Sept. 19, 2011

Ohio University paleontologist Patrick O'Connor is part of team of U.S. scientists that reported the discovery of a rare new species of raptor dinosaur in Utah this week.

The new dinosaur, named Talos Sampsoni, is a member of a group of feathered, bird-like theropods, also known as raptors. They're among the smallest non-avian dinosaurs and are known almost exclusively from Asia. Prior to the discovery of Talos sampsoni, only two species were recognized in the Late Cretaceous—a period 100 to 65 million years ago considered to be  the zenith of dinosaur diversity—of North America. 
Artist's rendering of Talos sampsoni by Jorge Gonzales. Courtesy/copyright of Utah Museum of Natural History.

"Finding a decent specimen of this type of dinosaur in North America is like a lighting strike," said Lindsay Zanno, lead author of the study, which was published in the journal PLoS ONE Monday. Zanno is an assistant professor of anatomy at the University of Wisconsin-Parkside and a research associate at the Field Museum of Natural History in Chicago.

Raptors have a terrifying reputation, in part because of the enormous talon on their foot. Yet the function of this claw has remained a somewhat of a mystery to paleontologists.  

The team's research reinforces the idea, however, that the dinosaurs used these big talons to either capture prey or fend off attackers.

In the new specimen found in Utah, the talon of the left foot is deformed, suggesting that the animal suffered a fracture or bite during its lifetime.  

To learn more about the injury to the animal's foot, the team scanned the individual bones using Ohio University's high-resolution Computed Tomography (CT) scanner, similar to those used by physicians to examine bones and other organs inside of the human body.  

"Although we could see damage on the exterior of the bone, our microCT approach was essential for characterizing the extent of the injury, and importantly, for allowing us to better constrain how long it had been between the time of injury and the time that this particular animal died," said O'Connor, associate professor of anatomy in the Ohio University Heritage College of Osteopathic Medicine

Patrick O'Connor

After additional CT scanning of other parts of the foot, the team found that the injury was restricted to the digit with the enlarged claw, but that the rest of the foot was not impacted.  More detailed study suggested that the injured toe was either bitten or fractured and then suffered from a localized infection.

"People have speculated that the talon on the foot of raptor dinosaurs was used to capture prey, fight with other members of the same species, or defend the animal against attack.  Our interpretation supports the idea that these animals regularly put this toe in harm's way," Zanno said.

The injured toe also shows evidence of bone remodeling thought to have taken place over a period of many weeks to months.

"It is clear from the bone remodeling that this animal lived for quite some time after the initial injury and subsequent infection. And that whatever it typically did with the enlarged talon on the left foot, whether that be acquire prey or interact with other members of the species, it must have been capable of doing so fairly well with the one on the right foot," said O'Connor, whose work is partly funded by the National Science Foundation.

The new species of dinosaur lived on the small island continent of Laramidia or west North America during the Late Cretaceous. A shallow seaway separated the continent into two landmasses for several million years. It was during this time that the dinosaurs achieved their greatest diversity, and scientists have been working to understand why.

Talos sampsoni
is the latest member of a growing list of new dinosaurs that have been discovered in Grand Staircase Escalante National Monument in southern Utah. Former President Clinton founded the monument in 1996, in part to protect the paleontological resources entombed within its 1.9 million acres of unexplored territory. The area has turned out to be a treasure trove of new dinosaur species, with at least 15 collected in just the past decade.

O'Connor has conducted fieldwork in Grand Staircase as part of a multi-institution effort to characterize the fauna and flora alive during the Late Cretaceous period.