The inside of a tyrannosaur skull has clues about how the most famous dinosaur and its powerful teeth evolved, according to researchers who used 3D imaging to scan the fossil. They took a high-energy CT scan of a 74-million-year-old skull that came from a dinosaur dubbed the Bisti Beast, which was found in northwestern New Mexico about 20 years ago and is related to the Tyrannosaurus rex, the Los Alamos National Laboratory reported, calling the work the highest resolution scan scientists have ever taken of a tyrannosaur. The skull needed high-energy imaging because it is so thick and the work gave them a closer look at the skull structure, including in the sinus and the brain cavities. The scan revealed impacted teeth hidden in the jaw and the pathways that some nerves and blood vessels took in the 3.5-foot-long cranium. "The results add a new piece to the puzzle of how these bone-crushing top predators evolved over millions of years," the New Mexico laboratory said.