Pint-sized T. rex unearthed in northern Alaska

Tegan Hanlon
Paleontologists from the Perot Museum of Nature and Science in Dallas have discovered a new genus and species of a tyrannosaur that once roamed the ancient Arctic lands of Northern Alaska. Formally named Nanuqsaurus hoglundi, the animal is a pygmy tyrannosaur, whose first name is in honor of the Iñupiat people whose traditional territory includes the land where these bones were found. The second name is in honor of Dallas entrepreneur and philanthropist Forrest Hoglund, whose extraordinary leadership helped raise $185 million to build the new Perot Museum, which opened in late 2012.
Dr. Tony Fiorillo on Alaska's North Slope at the excavation site, where Nanuq was discovered.
Photo courtesy of Perot Museum of Nature and Science
Silhouettes showing approximate sizes of representative theropods: A. Nanuqsaurus hoglundi (excavated in Alaska); B. Tyrannosaurus rex; C. Tyrannosaurus rex; D. Daspletosaurus torosus; E. Albertosaurus sarcophagus; F. Troodon formosus; G. Troodon. The scale bar at lower left equals 1 meter.

Texas-based paleontologists say they've excavated the fragmented bones of a new pygmy tyrannosaur, a Tyrannosaurus rex relative and the fiercest Arctic predator in northern Alaska.

The 25-foot-long animal was named Nanuqsaurus hoglundi, and its shrunken body, scientists say, suggests adaptation at the top of the world where profound swings in light and plant growth made life a challenge. Its first name means "polar bear lizard," nanuq being the Inupiaq word for polar bear, the modern arctic predator.

It took Anthony Fiorillo and Ronald Tykoski about six years to discover that the bones sitting in buckets at the Perot Museum of Nature and Science in Dallas belonged to a dinosaur never before identified. The two announced their discovery in a scientific journal report published Wednesday that has since attracted a lot of attention.

"As paleontologists, you're trying to study the history of life on earth and anytime you find something new you think it's cool and, in this particular case, I'm just kind of overwhelmed by the magnitude of the interest in this particular cool story," Fiorillo said in a phone interview.

The story started more than a decade ago.

Fiorillo, a curator of earth sciences at the museum, confirmed in 2002 that Kikak-Tegoseak Quarry was a dinosaur bone bed, thick in fossils and situated near the Colville River on the North Slope. By 2005, he had a three-year grant from the National Science Foundation, acquired appropriate permitting from the Bureau of Land Management and returned north to plan the excavation. He was particularly interested in horned dinosaurs.

Before then, paleontologists knew of about five plant-eaters and six meat-eating dinosaurs that roamed northern Alaska 70 million years ago, an area pushed as far as 85 degrees north, practically on the North Pole, said Pat Druckenmiller, earth sciences curator at the University of Alaska Museum in Fairbanks.

"So animals that lived up there had to cope with really long, dark winters if they stuck around, and from a variety of evidence, we feel that they probably did stick around over the winter months," he said.

Back then, it was warmer. Where there's now tundra, there was once forested woodland with small trees and flowering plants, said Druckenmiller.

For a month in the summer of 2006, Fiorillo and a team of four set up camp on the Colville River, about 400 miles northwest of Fairbanks. They paddled inflatable watercraft to the dig site. They'd tie up along the shore and scale the 250-foot bluff every day. To the north, Fiorillo saw rolling tundra, and to the south, the Brooks Range on the horizon.

The team hacked away at the permafrost a few inches at a time with hammers and shovels, only pausing to let the sun melt away the ice so they could scoop off the next layer.

That summer, they excavated about 11,000 pounds of material as part of an ongoing project and discovered a new species -- not the Nanuqsaurus hoglundi, that came later -- a plant-eating horned dinosaur called the Pachyrhinosaurus perotorum.

"Well, the horned-dinosaur thing occupied all of our attention, it was the gem, crown jewel of the project," he said. They didn't know the other new species of tyrannosaur was in the rubble.

The team scooped up the material that surrounded the plant-eater's skull, about 950 pounds of it, flew it to Fairbanks and sent it on a truck to Dallas. There was a football-sized block of rock in there, believed to contain tyrannosaur bones. It got pushed aside while Fiorillo and Tykoski prepared for the museum's 2012 opening.

But as other researchers began publishing papers on different species of tyrannosaurs, Tykoski said he thought it was time for another look at the block. So he began chipping off 70 million years' worth of sediment and what he found puzzled both him and Fiorillo.

They found "ridiculously tiny" teeth in the front of a lower jaw. "They were so dinky you look at them and go, 'Really?' " said Tykoski. Then, there was a bone from the snout with a very specific suture pattern, only seen in adult Tyrannosaurus rex and a tyrannosaur of central Asia. But the skull was far too small to be one of these big predators.

"So we have an adult animal that looks like a Tyrannosaurus rex but it's half the size of the Tyrannosaurus rex," Fiorillo said.

And so became the Nanuqsaurus hoglundi, a meat-eating dinosaur weighing about 1,000 pounds. Fiorillo described it as a "close cousin of the Tyrannosaurus rex, it's not a second cousin, twice-removed sort of thing."

In northern Alaska it was "the top dog," he said.

Reach Tegan Hanlon at or 257-4589.