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. 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 thickness of the skull, which spans 40 inches (102 centimeters), required stronger X-rays than those typically available to penetrate the 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.

Source: ABC News August 15, 2017 19:33 UTC