Perot Dinosaur Grows Up

Paleontologists from Dallas' Perot Museum of Nature and Science uncover juvenile specimen in same North Slope Alaskan site where Pachyrhinosaurus perotorum was discovered

Jun 20, 2013, 10:05 ET from Perot Museum of Nature and Science

DALLAS, June 20, 2013 /PRNewswire-USNewswire/ -- Just 20 months after announcing their discovery of a new species found in Alaska called the Pachyrhinosaurus perotorum, paleontologists from the Perot Museum of Nature and Science in Dallas have since uncovered a juvenile specimen that came from the same hole in the ground. The scientific paper describing the find – entitled "An immature Pachyrhinosaurus perotorum (Dinosauria: Ceratopsidae) nasal reveals unexpected complexity of craniofacial ontogeny and integument in Pachyrhinosaurus" – was posted late yesterday on the prestigious science journal PLOS ONE, an international, peer-reviewed, open-access online publication featuring reports on primary research from all scientific disciplines. Dallas paleontologist Anthony R. Fiorillo, Ph.D., the Perot Museum's curator of earth sciences, and Ronald S. Tykoski, Ph.D., fossil preparator at the Museum, co-authored the report. To read Dr. Fiorillo and Dr. Tykoski's entire manuscript, go to PLOS ONE at


"In our early years of work, we initially thought we had only had one age profile – that of an adult. But as the preparation work has continued in recent years on the additional blocks from that same Alaskan expedition site, it was a true 'aha' moment to find the younger skull as well," said Dr. Fiorillo.

Dr. Fiorillo discovered the adult version of the Pachyrhinosaurus perotorum during a return excavation in 2006 to Alaska's North Slope (Prince Creek Formation: Maastrichtian), many miles north of the Arctic Circle. In October 2011, the species was formally named Pachyrhinosaurus perotorum in recognition of the Perot family (Margot and Ross Perot and their children) for their long-term commitment and support for science education.

After transporting more than 12,000 pounds of cargo by air and highway from Alaska to the Museum's paleontology labs in Dallas, the jackets were given handed over to Dr. Tykoski, who handles and oversees all the preparation work at the Perot Museum. He and his team of staff and volunteers began the painstaking task of meticulously whittling away the 70 million-year-old sediment entombing the dinosaur bones.

The discovery of the juvenile came in 2012 when Dr. Tykoski was working on a football-sized block focusing on a strip of bone about an inch wide exposed at the surface. One of the key diagnostic features of the Pachyrhinosaurus perotorum is the top of the nose. The juvenile specimen has a small, narrow horn on the snout that, after puberty, grows and thickens into a lumpy, battering ram-like bulge, a mark that distinguishes the Pachyrhinosaurus perotorum.

"After a couple weeks of working on it, our question was 'what on earth is this?' It had features on it that looked like the big adult skull of the Pachyrhinosaurus perotorum that we had originally found, yet it was very narrow and skinny and didn't have the big expanded nose of the adult," said Dr. Tykoski. "After ruling out all of the possibilities through the process of elimination, we realized this was a juvenile specimen. This provided us a snapshot in the development of the species – and that's not common – so this was a very exciting moment for us."

Dr. Fiorillo added that "this discovery helps us realize that this unique polar dinosaur isn't just a trophy on the wall, but was a living, breathing animal."

"The finding of this juvenile implies that the Artic, which was believed to be too harsh a climate for dinosaurs to survive, was an environment not only ripe for productivity, but shows that the species of Pachyrhinosaurus perotorum was reproducing and living there contentedly," added Dr. Fiorillo. 

A display featuring the adult Pachyrhinosaurus perotorum currently is installed in the T. Boone Pickens Life Then and Now Hall, a 14,000-square-foot hall in the Perot Museum of Nature and Science, which opened December 1, 2012, near downtown Dallas. On view are the actual skull and grill fossils that Dr. Fiorillo found on Alaska's North Slope along with a 3D model of the animal and a richly colored, wall-sized illustration created by artist Karen Carr.

To learn more about the Perot Museum of Nature and Science, visit

Becky Mayad

SOURCE Perot Museum of Nature and Science