Researchers uncovered a fossil timeline of the first million years after the dinosaurs went extinct in Colorado's Corral Bluffs. As seen in these fossils, the mammals grew larger over time. These four mammal skulls represent Loxolophus, Carsioptychus, Taeniolabis and Eoconodon (left to right).
Tyler Lyson used a rock hammer to split open concretions found at the site. Concretions are egg-shaped rocks that form around an organic nucleus like bone.
This split concretion reveals the cross section of a vertebrate skull inside.
A collection of mammal skull fossils and lower jaws retrieved from Corral Bluffs.
This is a skull of Taeniolabis taoensis, which appeared approximately 700,000 years after the mass extinction event. It was an herbivore that came on the scene at the same time as the world's oldest legume plant fossil.
This is a CGI rendering of the ancient Taeniolabis mammal. The rendering was taken from the PBS NOVA special "Rise of the Mammals."