TOKYO - New research is reshaping long-held assumptions about Tyrannosaurus rex, including suggestions that the giant predator may have lived to around 40 years rather than 28, while advances in fossil analysis are also offering new clues about dinosaur growth, posture and even color. One major debate has concerned Nanotyrannus, a smaller tyrannosaur once widely interpreted as a juvenile form of Tyrannosaurus rex. That would mean North America about 66 million to 68 million years ago was home not only to Tyrannosaurus rex but also to another, smaller tyrannosaur. The latest work has therefore suggested that the lifespan of Tyrannosaurus rex could have extended to around 40 years. No such evidence has yet been found that reveals the color of Tyrannosaurus rex.