The revolutionary find, the first of its kind in North America, came last summer and ensuing studies on the fossils showed that pre-dinosaurs likely lived alongside dinosaurs for more than 15 million years, the Chicago Sun-Times said Friday.
The research group dubbed its species Dromomeron romeri, now part of the basal dinosauromorphs scientific classification.
The fossils are about the size of a dog and researchers said the animal likely was a plant-eater.
One member of the research team that located the fossils was 27-year-old graduate student Nathan Smith, who said the discovery was an amazing find for his early career in paleontology.
"I consider myself lucky," the University of Chicago student told the newspaper. "A lot of things have worked out well."
"Hopefully, I haven't peaked yet," he jokingly added.