Jennifer Cavin was uncasting a large dinosaur fossil excavated in southeastern Utah, removing the protective plaster, when she made a discovery within the discovery.
There, tucked beneath the foot of the herbivore she was working on, was a fossilized cranium. The weird thing: It didn’t appear to belong to a reptile. Jim Kirkland knew that almost immediately when he rushed over to see it. This wasn’t like the other dinosaurs — lizards and raptors — they’d been uncovering. The state paleontologist was stunned.
Whatever the critter was, Kirkland told Cavin, it was more like a mammal than anything else.