"Scientists Declare Tiny Tyrannosaurs a Unique Species, Ending T. rex Debate"
Scientists from the University of Bath have resolved a long-standing debate by determining that certain fossilized skulls, originally thought to be from juvenile Tyrannosaurus Rexes, actually belong to a different species, the Nanotyrannus lancensis. The conclusion was drawn from analysis of growth rings in the bones and growth modeling, which showed that the dinosaurs in question were not growing at the rate expected of young T. Rexes. The study, which changes our understanding of these prehistoric creatures, was published in the journal Fossil Studies.