A monumental breakthrough occurred in 2016 when Lyson and Miller concentrated their efforts in an area called Corral Bluffs. They believed this Denver Basin locale showed promise because a handful of relatively complete vertebrate fossils had been found there over the decades.

So, they set their eyes to the ground, looking for bits of bone, the way they were trained to find fossils. They came up with only fragments.

However, Lyson was convinced they weren’t keying in on the right material, perhaps not seeing what was right in front of their noses. He recalled his fossil hunting experience with South African colleagues in the deserts of the Karoo, where the key to finding fossils was not searching for bone fragments but for a particular kind of rock called a concretion.

So what if the team searched Corral Bluffs for concretions instead of the usual bone? It was the light bulb moment that changed the game completely.