Tyrannosaurus rex: it was not one species but three different ones.
The big lie that we had told ourselves about the Tyrannosaurus rex: it was not one species but three different ones.
"Having a name only increases the fear of what is named," said the famous animal activist H. J. Granger, but who is not going to be afraid of a bug that is 13 meters long and weighs 9 tons? Who is not going to be horrified by those sharp teeth, those claws, that mass of flesh and bone, and ravenous hunger running at more than 30 kilometers per hour? In this case, fearing the name of Tyrannosaurus rex is a direct consequence of what was named: one of the gigantic predators in the history of the Earth.
Pieces that don't fit... That's partly why we've become obsessed with them, we've studied them carefully, and we haven't stopped rebuilding them. However, we have never fully understood them. It was as if the pieces did not quite fit together, as if what we knew about the ontogenetic development of the animal did not quite form an organic whole.
For example, bones in the fossil record varied in density and robustness. Moreover, we found specimens that had one pair of incisors but also specimens that had two pairs.
"...because they are not from the same puzzle". Gregory Paul and his team decided to turn the question around. They studied 37 specimens attributed to T. rex and analyzed the length and circumference of the thigh bones with the idea of evaluating their robustness. Their strange conclusions make sense: it is doubtful that the differences between the analyzed bones are due to individual variations.
Too significant a variance not to be suspicious. "We found that the robustness in the sample we have of tyrannosaur, the variation of the femur is greater than that of all other tyrannosaurids combined over 10 million years of evolution," Paul explained. We are talking about differences too significant not to set off all the alarms. Above all, the differences in density are not related to the total size of the specimen or the estimated age at the time of death. It doesn't seem to be a gender issue either.
Three species. Obviously, there is still a lot of material to be cut. All the alternative explanations cannot be ruled out, and some paleontologists are not entirely convinced. Still, the team is clear that the one that best fits is that were until now, we have seen only one Tyrannosaurus rex. There are three: rex, imperator, and Regina.
The idea is suggestive. Above all, because it is the most extensive study done to date and explains some things that, until now, had been difficult to fit. However, it runs into the same kind of problems that all dinosaur studies run into: there is little material to study in-depth. And, even if we have it, we have the example of the pens to know how much it costs to eliminate a social image when it is well established.