A dinosaur scientist in Rapid City has solved a 100-year-old mystery with a CAT scan, which takes multiple X-rays from different directions.

The species of dinosaur in a 2-inch egg was yet to be determined until a South Dakota School of Mines & Technology assistant professor combined the medical technology with scientific instinct.

Using a CAT scan, Gerald Grellet-Tinner was able to see through the shell to view the bones that had been formed in the embryo.

Grellet-Tinner discovered that the dinosaur embryo comes from a type of triceratops.