This past week we hosted paleontologist Thomas Carr from Carthage College in Wisconsin.  Thomas studies Tyrannosaurus rex. Because we have one of the best T.rex collections in the world, T.rex specialists often visit the Museum of the Rockies.  Thomas was here for several projects he is working on and also to visit with me concerning a project to determine if Nanotyrannus and Tyrannosaurus rex could possibly be the same animal but represent different growth stages.  The biggest difference between these two tyrannosaurs besides size is that T.rex has 12 to 13 teeth in each of its lower jaws, whereas smaller Nanotyrannus has 17 in each jaw.  No other dinosaurs are known to lose teeth during growth, so if these two species were to be discovered to represent a single species it would show that T.rex did something no other dinosaur is known to have done.  To try to figure this out we took several tyrannosaur jaws to the Bozeman hospital and had them X-rayed so that we could study the inside of the jaws to see how the teeth grow.  One of these days we will let you know what we have discovered.

Photo of Bozeman hospital workers x-raying tyrannosaur jaws from Ellen Therese-Lamm