Ancestors of Tyrannosaurus Rex

Video Transcript

"Now for two antecedents of the mighty T-Rex. The first was a Diplosaurus here. That means the double ridged Dino, because of the two ridges on his forehead. Dilly here existed in the early Jurassic period. And he was actually a predatory dinosaur that had two arms that are held out much like other dinosaurs. He could use these, and he weighed about oh, five to ten tons, was about ten feet tall and lived in herds as far as we know. As far as those two ridges on his head, it's possible they were for display or for bucking. Just as deer?s buck in herds to try to find out who's going to assume dominance, some Dinos might've done that. That's why we think he may have lived in a herd. Because he might have had this protection of those two ridges to buck another Dino like that. Or they might have just been for display to try to attract mates. They might have been slightly different in color, we don't know about the coloration of the Dinos. But see that we have these slightly different in color maybe that would've attracted mates. But certainly it may have had some purpose. Now the other relative of T-Rex was the Ceratosaurus here, found in the Middle Cretaceous Period. He has two tiny little horns, yet his name Ceratosaurus means the horned Dinosaur. certainly not appropriate when you consider other Dinos who had much more prominent horns. Again, they might have been for protecting his head in bucking, for defense or display. Now notice that his arms are now as best we can show on this model, significantly shorter than the Dilly's arms here. And that's because these Dinos were losing the use of their arms over time, as you'll see with T-Rex in the next segment. Now may I say there's another Dino related to this, the Alosaurus, perhaps better known. This creature stood about ten to fifteen feet. Again, another vicious predator. And I should point out with all the Dinosaurs, with their tails, when they moved the tail was off the ground for proper balance. It was not dragging. Yes, the Ceratosaurus."