Nanotyrannus Adolescent Tyrannosaurus rex Juvenile Tyrannosaurus rex Adolescent fossil Fossilized remains Juvenile specimen Fossil Record Paleoart Juvenile vs. Adult Nanotyrannus lancensis Distinctive features Growth variation Growth Patterns Physical Characteristics Species Classification Debate Tyrannosaurus mcraeensis Evolution Fossil analysis Species discovery Tyrannosaur lineage Tyrannosaurus mcraensis Skull Jaw Teeth New subspecies of tyrannosaur Fossils Subspecies Ancestors North America Evolutionary chain Physical characteristics Origin Characteristics Diet Distribution Juvenile T. rex Intelligence