In what scientists at the North Carolina Museum of Natural Sciences are calling the dinosaur discovery of the decade, North Carolina researchers have identified a new species of dinosaur.
For more than a year, paleontologists in the SECU DinoLab at the North Carolina Museum of Natural Sciences — the world’s only paleontology preparation lab that is regularly open to the public — have been studying the 67-million-year-old Dueling Dinosaurs fossils.
The Dueling Dinosaurs were found in the Hell Creek Formation of Montana by ranchers in 2006, and the find included the fossilized skeletons of a tyrannosaur and a triceratops entangled with one another, and entombed in sandstone.
They’re called "dueling" dinosaurs because of the numerous injuries to both, although it is not known whether they were actually buried fighting one another.
The ranchers that found the fossils tried unsuccessfully to sell them to several museums for years, then tried to sell the specimen to a private buyer, also to no avail.
In 2016, Lindsay Zanno, the museum’s head of paleontology, started negotiations to purchase the fossil, with funds raised through the private nonprofit Friends of the North Carolina Museum of Natural Sciences. Those negotiations were slowed but a court ruling that fossils could legally be considered minerals in Montana, but, in an appeal, the Montana Supreme Court overturned that decision in 2020, paving the way for the Dueling Dinosaurs exhibit – and research -- at the museum in Raleigh.
Zanno said the Tyrannosaur fossil is among the most complete ever found. “We had this incredible skull to work with,” she said, “So we knew we needed to use the most cutting-edge technology to see inside that skull, to look at the bones that we couldn't see with our naked eye. And so, we took this skull all over the U.S. to several CT and synchrotron scanning facilities so that we could peer inside and reconstruct the internal anatomy of the Dueling Dinosaur tyrannosaur skull.”
And, in doing the scans she said a long-held suspicion among some paleontologists was confirmed – the specimen wasn’t simply a teenage Tyrannosaurus rex.
“What we found in doing all of this is that the unique pattern of sinuses and the way the bones articulate in the skull and the pattern of cranial nerves in our Tyrannosaur here at the museum most closely matches the morphology that we see of the skull that has the name Nano Tyrannus lancensis,” she said.
Nano Tyrannus lancensis was first identified in the 1940s and later largely dismissed by the paleontological community as just a younger T-rex. But she said the research confirmed the differences between the two Tyrannosaurs were far greater than just size.
“All these things that are different about the skull of Nano Tyrannus, from the nerve patterns to the sinus orientations, and lots of the orientations of the bones and teeth and other features, these are not things that change as dinosaurs or even living animals today grow from babies to adult,” Zanno explained, “These are things that are fixed very early in the development of an animal, and they stay the same as that animal grows up.”
And the studies also disproved another long-held belief about the T-rex. Zanno said, “For a long time, we thought that Tyrannosaurus Rex was the only Tyrannosaur and the only major predator in these famous ecosystems of western North America just before the asteroid impact. We now know that running alongside that massive, heavily built predator with powerful bite forces and teeth the size of bananas was a tiny, fast, predator that could have run under the legs of T. rex, a pursuit predator built for speed called Nano Tyrannus.”
She said they determined the animal was mature and done growing when it died around the age of 20 – not long before a massive asteroid wiped out most of the non-avian dinosaurs and about 75% of all species on Earth.
It’s about half the size and a tenth of the mass of a full-grown Tyrannosaurus rex. Nano Tyrannus weighed about 1,500 pounds -- compared to about 14,000 to 18,000 pounds that an adult T. rex typically weighed.
Skeletal features like larger forelimbs, more teeth, fewer tail vertebrae, and distinct skull nerve patterns also distinguish Nano Tyrannus from T. rex.
“We think we've identified a new cryptic species of Nano Tyrannus that's been hiding under our nose the entire time,” Zanno said, “And so, we've named a new species of Nano Tyrannus, Nano Tyrannus litheus. So now we have not just one or two, but three predators living within the last million years of the Cretaceous in one of the best-known ecosystems that paleontologists have been hunting dinosaurs for in over a century.”
Zanno said the discovery flips decades of T. rex research on its head.
