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Unique Imaging of a Dinosaur’s Skull Tells Evolutionary Tale

August 15th, 2017

(Albuquerque, NM)—Researchers using Los Alamos’ unique neutron-imaging and high-energy X-ray capabilities have exposed the inner structures of the fossil skull of a 74-million-year-old tyrannosauroid dinosaur nicknamed the Bisti Beast in the highest-resolution scan of tyrannosaur skull ever done. The results add a new piece to the puzzle of how these bone-crushing top predators evolved over millions of years.

“Normally, we look at variety of thick, dense objects at Los Alamos for defense programs, but the New Mexico Museum of Natural History and Science was interested in imaging a very large fossil to learn about what’s inside,” said Ron Nelson, of the Laboratory’s Experimental Physical Sciences Division. Nelson was part of a team that included Los Alamos National Laboratory, the museum, the University of New Mexico and the University of Edinburgh. “It turns out that high energy neutrons are an interesting and unique way to image something of this size.”

The results helped the team determine the skull’s sinus and cranial structure. Initial viewing of the CT slices showed preservation of un-erupted teeth, the brain cavity, internal structure in some bones, sinus cavities, pathways of some nerves and blood vessels, and other anatomical structures. These imaging techniques have revolutionized the study of paleontology over the past decade, allowing paleontologists to gain essential insights into the anatomy, development and preservation of important specimens. Team members will present their findings on the beast, Bistahieversor sealeyi, August 23 at the annual Society of Vertebrate Paleontology meeting in Calgary, Alberta.

To peer inside the 40-inch skull, which was found in 1996 in the Bisti/De-Na-Zin Wilderness Area near Farmington, N.M. the Los Alamos team combined neutron and X-ray computerized tomography (CT) to extract new anatomical information. Los Alamos has the unique capability in the country to perform both methods on samples ranging from the very small to the very large scale.

The thickness of the skull required higher energy X-rays than those typically available to adequately penetrate the fossil. The Lab’s microtron electron accelerator produced the high-energy X-rays.

To provide an alternate view inside the skull, the team also used a newly developed, high-energy neutron imaging technique with neutrons produced by the proton accelerator at the Los Alamos Neutron Scattering Center (LANSCE). The neutrons interact with the nuclei rather than the electrons in the skull, as X-rays do, and thus have different elemental sensitivity. This provides complementary information to that obtained with X-rays.

The team’s study illuminates the Bisti Beast’s place in the evolutionary tree that culminates in the Tyrannosaurus rex.

“The CT scans help us figure out how the different species within the T. rex family related to each other and how they evolved,” said Thomas Williamson, Curator of Paleontologist at the New Mexico museum. “The Bistahieversor represents the most basal tyrannosaur to have the big-headed, bone-crushing adaptations and almost certainly the small forelimbs. It was living alongside species more closely related to T. rex, the biggest and most derived tyrannosaur of all, which lived about 66 million years ago. Bistahieversor lived almost 10 million years before T. rex, but it also was a surviving member of a lineage that retained many of the primitive features from even farther back closer to when tyrannosaurs underwent their transition to bone-crushing.”

“More than a century after the first tyrannosaur fossils were discovered, these new neutron and x-ray scans are giving us the best look yet at the skull anatomy and sensory abilities of these famous dinosaurs. The scans are helping us understand how the biggest predators that ever lived on land would have sensed their world,” said Steve Brusatte, paleontologist at the University of Edinburgh.

The Bisti Beast skull is the largest object to date for which full, high-resolution neutron and X-ray CT scans have been performed at the Laboratory and required innovations both to image the entire skull and to handle the image reconstruction from the resulting large data sets.

This work advances the state of the art in imaging capabilities at the Laboratory and is already proving useful in imaging larger programmatic items related to the Laboratory’s national security mission. 



Video Link:​

About the project:

This work was funded by Los Alamos National Laboratory capability development funds from the Applied Engineering and Technology division and from National Nuclear Security Administration Science Programs, and through a grant to UNM through the New Mexico Consortium. The team comprised Michelle Espy, Cort Gautier, James Hunter, Adrian Losko, Ron Nelson, and Sven Vogel, of Los Alamos National Laboratory; Tom Williamson, Curator of Paleontology at the New Mexico Museum of Natural History and Science; Kat Schroeder, of the University of New Mexico and Steve Brusatte, School of GeoSciences of the University of Edinburgh, Scotland.

About Los Alamos National Laboratory (

Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, BWX Technologies, Inc. and URS Corporation for the Department of Energy’s National Nuclear Security Administration. Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction and solving problems related to energy, environment, infrastructure, health and global security concerns.

About the New Mexico Museum of Natural History & Science:  Established in 1986, the New Mexico Museum of Natural History and Science’s mission is to preserve and interpret the distinctive natural and scientific heritage of our state through extraordinary collections, research, exhibits and programs designed to ignite a passion for lifelong learning. The NMMNHS offers exhibits, exhibitions, programs, and workshops in Paleontology, Geoscience, Bioscience, Earth Science, Natural Science, Gemology and is the Southwest’s largest repository for dinosaur fossils, and includes a Planetarium and a DynaTheater. A division of the New Mexico Department of Cultural Affairs, the Museum is open 7 days a week, from 9am-5pm, closed Thanksgiving, Christmas, and New Year’s Day. Located at 1801 Mountain Road NW, northeast of Historic Old Town Plaza, Albuquerque, NM 87104, (505) 841-2800.


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Excavation of Bisti Beast (1996) in the Bisti/De-Na-Zin Wilderness Area near Farmington, N.M. Ray Nelson, Courtesy: NM Museum of Natural History & Science

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