An article published in the journal “Science Advances” reports a study that offers an analysis of the fossils of what was classified as Nanotyrannus offering evidence that actually they’re young specimens of Tyrannosaurus rex. A team of researchers led by Dr. Holly Woodward of the Oklahoma State University Center for Health Science conducted a paleohistological examination on bone fragments of the specimens nicknamed Jane and Petey concluding that fibers and other microstructures were growing. According to their estimates, Jane was around 13 years old at the time of death while Petey was around 15 years old.