Penn grad student identifies new dinosaur, a relative of Velociraptor

Anyone who has seen Steven Spielberg’s blockbuster film “Jurassic Park” likely has an image of a Velociraptor—depicted in the movie as large, aggressive, green monsters with razor-sharp claws and teeth—seared in their brain. And even though the real-life “raptors,” contrary to the film’s depiction, had feathers and were the size of a chicken, a newly discovered relative may have indeed been a formidable predator.

Steven Jasinski, a doctoral student in the Department of Earth and Environmental Science in the School of Arts & Sciences, identified the new species, which he has named Saurornitholestes sullivani, based on a portion of a fossilized skull that was originally believed to belong to another species, Saurornitholestes langstoni.

The skull was found in 1999 in New Mexico by paleontologist Robert Sullivan. Roughly 75 million years old, the animal lived in the Late Cretaceous period, near the end of the age of dinosaurs. It would have roamed the Earth along with dinosaurs such as the duck-billed hadrosaurs Parasaurolophus tubicen and Kritosaurus navajovius, the horned dinosaur Pentaceratops sternbergii, and the tyrannosaurs Bistahieversor sealeyi and Daspletosaurus.

Though the specimen was clearly a dromaeosaur, otherwise known as a raptor, Jasinski, who is studying under Peter Dodson, a professor of anatomy and paleontology, noticed a few features that could set it apart from the previously described S. langstoni. To clear up confusion, Jasinski began what he calls “a slow process” of comparative anatomy, using manual measurements and photogrammetry, which can reveal three-dimensional brain measurements.

His analysis revealed a number of subtle distinctions between the specimen and the reference specimen of S. langstoni, offering evidence that this represented a new species. One difference that stood out was the large size of the skull surface corresponding to the brain’s olfactory bulb, suggesting this dinosaur had a powerful sense of smell.

“This feature means that Saurornitholestes sullivani had a relatively better sense of smell than other dromaeosaurid dinosaurs, including Velociraptor, Dromaeosaurus, and Bambiraptor,” Jasinski says.

S. sullivani measured less than 3 feet at the hip and 6 feet long from nose to tail, but its sense of smell would have made it a “formidable predator,” Jasinski notes. It is likely that these dinosaurs hunted in packs, preying upon mammals, lizards, and perhaps even juvenile dinosaurs.

“Although it was not large, this was not a dinosaur you would want to mess with,” Jasinski says.

UPenn Dinosaur