Researchers at a top US laboratory announced on Tuesday that they have produced the highest resolution scan ever of a fossilized tyrannosaur skull. The scan uses neutron beams and high-energy X-rays has helped in finding new clues that could help paleontologists to piece together the evolutionary puzzle of the monstrous T. rex.

Officials with Los Alamos National Laboratory and the New Mexico Museum of Natural History and Science said they were able to peer deep into the skull of a “Bisti Beast,” a T. rex relative that lived millions of years ago in  northwestern New Mexico.

The image details the dinosaur’s brain and sinus cavities, the pathways of some nerves and blood vessels and teeth that formed but never emerged.

Thomas Williamson, the museum’s curator of paleontology and part of the team that originally collected the specimen in the 1990s, said the scans are helping paleontologists figure out how the different species within the T. rex family relate to each other and how they evolved.

“We’re unveiling the internal anatomy of the skull so we’re going to see things that nobody has ever seen before,” he said during a news conference Tuesday.

T. rex and other tyrannosaurs were huge, dominant predators, but they evolved from much smaller ancestors.

The fossilized remnants of the Bisti Beast, or Bistahieversor sealeyi, were found in the Bisti/De-Na-Zin Wilderness Area near Farmington, New Mexico. Dry, dusty badlands today, the area in the time of the tyrannosaur would have been a warmer, swampy environment with more trees.

The species lived about 10 million years before T. rex. Scientists have said it represents one of the early tyrannosaurs that had many of the advanced features – including big-headed, bone-crushing characteristics and small forelimbs – that were integral for the survival of T. rex.

Officials said the dinosaur’s skull is the largest object to date for which full, high-resolution neutron and X-ray CT scans have been done at Los Alamos. The technology is typically used for the lab’s work on defense and national security.

The thickness of the skull, which spans 40 inches (102 centimeters), required stronger X-rays than those typically available to penetrate the fossil. That’s where the lab’s electron and proton accelerators came in.

Sven Vogel, who works at the Los Alamos Neutron Science Center, said the three-dimensional scanning capabilities at the lab have produced images that allow paleontologists to see the dinosaur much as it would have been at the time of its death, rather than just the dense mineral outline of the fossil that was left behind after tens of millions of years.

The team, which included staff from the University of New Mexico and the University of Edinburgh, is scheduled to present its work at an international paleontology conference in Canada next week.

Kat Schroeder, a Ph.D. candidate at the University of New Mexico who has been working on the project for about a year, said the scanning technology has the ability to uncover detail absent in traditional X-rays and the resulting three-dimensional images can be shared with fellow researchers around the world without compromising the integrity the original fossil.

Schroeder’s work centers understanding the behavior of dinosaurs, so seeing the un-erupted teeth in the Bisti Beast’s upper jaw was exciting.

“Looking at how fast they’re replacing teeth tells us something about how fast they’re growing, which tells me something about how much energy they need and how active they were,” she said. “It’s those little things that enable us to understand more and more about prehistoric environments.”

(Top photo: New Mexico Museum of Natural History and Science paleontology curator Thomas Williamson talks about the results of neutron and X-ray scans of a fossilized tyrannosaur skull during a news conference at the museum in Albuquerque, N.M., on Tuesday, Aug. 15, 2017. Williamson discovered the fossil remains of the “Bisti Beast” in 1996 and worked with researchers at Los Alamos National Laboratory last fall to scan the skull in hopes of gleaning new information about the evolution of the massive, bone-crushing dinosaurs. /AP Photo, Susan Montoya Bryan)