Nearly complete tyrannosaur fossil airlifted from Utah’s Grand Staircase

Two years ago, Alan Titus was prospecting for fossils on Utah’s Kaiparowits Plateau, searching for new places to unearth paleontological treasures that could reveal secrets about massive and long-extinct land reptiles known as dinosaurs.

Protruding from sandstone he saw some vertebrates, not an uncommon sight in this corner of the Grand Staircase-Escalante National Monument that has become renowned as one of the world’s most productive repositories of dinosaur bones dating to the Cretaceous.

But over the next several months of excavation, what Titus, the monument’s resident paleontologist, and colleagues from the Natural History Museum of Utah found was anything but common.

Coming into focus was a well-articulated, nearly complete tyrannosaur, the notorious flesh-ripping, tiny-armed predator.

“It looks like we have the entire skull and most of the body,” said Randy Irmis, the museum’s paleontology curator. “The back part of tail is missing and a few toes. We don’t know yet if the arms are there.”

On Sunday, Titus and museum staffer Tylor Birthisel deployed a helicopter to extract the specimen. It was encased in plaster and flown out in pieces, the largest weighing nearly a ton, for shipment to Salt Lake City.

So far, it appears to be 80 percent intact, the most complete tyrannosaur ever recovered in the American Southwest.

Researchers believe the specimen is a teratophoneus, a relative of T. rex that stood about 12 feet tall and roamed the Earth several million years before its more famous cousin.

The genus name means “monstrous murderer” and was first characterized by Thomas Carr and Thomas Williamson in 2011. The species has been found only in the Grand Staircase.

“This discovery exemplifies the uniqueness of the fossils in the the Staircase,” Irmis said. “Regardless if it‘s a teratophoneus or something new, these are things found only in Grand Staircase. These are world-class paleontological resources.”

That part of the Grand Staircase also contains 9 billion tons of another extractable resource: high-quality, low-sulphur coal.

Interior Secretary Ryan Zinke’s undisclosed monument-reduction recommendations are believed to call for pulling the Kaiparowits out of the monument. A leaked memo to President Donald Trump indicates Zinke wants to shrink Grand Staircase, Bears Ears and two other Western monuments, but it does not provide specifics.

Titus’s specimen was embedded in the famed Kaiparowits Formation, a layer of sandstone 2,800 feet thick deposited 76 million to 74 million years ago, just 7 million years before an astroid wiped out most large-bodied animals on Earth.

The discovery could advance dinosaur science because the bones are still together, as if the animal was preserved in the very position in which it died.

“A lot of the bones are articulated. A few things are out of place, but most [of it] is in a life position,” Irmis said. “In fossil records carnivores are rarer than herbivores. These apex predators are the rarest because they are at the top of the food chain.”

It is unusual to find much of any single dinosaur since so many things can destroy bones over the course of time, including decay, scavengers, weather and geologic forces. This specimen was in the early stages of being exposed when Titus spotted it.

“It has to be exposed for us to find it but not so much that erosion destroys it,” Irmis said. He said he believes the dinosaur’s carcass was buried in a river channel or in a flooding event.

“We still have to do more geological work to figure which it is,” he said.

The find is fortuitous because the museum has specimens representing adult and young teratophoneus. This one, about 17 feet to 20 feet in length, is a juvenile, giving researchers a more complete picture of the creature.

“It can tell us how they change as they grow older,” Irmis said. “Having a complete skeleton helps answers those questions.”