A new study says the best-known dinosaurs of all time corresponded to at least three different species that had subtle distinctions from each other in terms of anatomy, when they lived and perhaps in behavior.
Hypothesis proposed by a trio of American researchers may refute the classification of the famous tyrannosaurus rexTwo other species established: T. imperator and T. regina.
Not coincidentally, all scientific names are variations of “rex” or “re” in Latin – “regina” means “queen” and “imperator”, of course, “emperor” in the native language of Portuguese.
The Analysis That Underlies the “Triple Personality” From tyrant It is now published in the scientific journal Evolutionary Biology. The study was coordinated by independent researcher Gregory Paul and is also signed by Scott Persson and Jay Van Ralte from the College of Charleston, South Carolina.
about 12 meters long, tyrannosaurus rex 68 million to 66 million years ago lived in a wide area that would become present-day North America. Both the vast geographic distribution and the duration of the animal’s existence open the possibility that speciation events have occurred, that is, the formation of new species of tyrannosaurs from a common ancestor.
Paul and his colleagues T. rex, one of the most well-studied dinosaur species with relatively abundant skeletons. For example, it is known that there were more graceful forms (ie with relatively light bones) and that the animal had other more robust forms. In addition, there are variations in beginners.
Some animals have only one tooth on each side of the jaw called the insiform (by analogy with mammals’ rodents), while others have two iniformes.
The scientists’ goal was to assess how these differences compared to the variability of other dinosaurs, both in relative terms (being larger or smaller than the differences distinguishing other species) and over time.
This type of analysis would also help predict whether T. rex variability may correspond only to natural differences between individuals (such as between tall and short humans, say) or whether it may be linked to sexual dimorphism, i.e. distinction between males. And female.
Gregory Paul and his colleagues in T. rex, which made it possible to analyze the femur (thigh bone) strength of 24 animals. Only 12 of them had both teeth and femurs available.
One of the main findings is that the variability in bone strength is as high as 30%, which is higher than what you see in related dinosaurs that are grouped together.
Older forms are stronger and have two smaller incisors, while newer forms include both strong and graceful animals with only one incisors.
This prompted researchers to propose that the oldest robust form, with two insiforms, would be named T. imperator, while the more recent would be T. rex proper (also stronger) and T. reginae (more beautiful). , both with a single incision.
Was there any difference in the habits of the three? For Paul, one possibility would be a difference in prey, with more robust animals specializing in attacking the mighty Triceratops herbivores, which resemble dinosaur-sized rhinos.
“It appears that the stronger T. rex and the more gracious T. regina were living together at the end of the Cretaceous. The other may have evolved to hunt edmontosaurs. [herbívoros com bico semelhante ao de patos] -We have their skeletons with tail injuries that suggest this possibility,” the researcher said. Bedsheet,
to the paleontologist Rafael Delcourt, an expert in the evolution of big dinosaur Carnivorous and postdoctoral researcher at USP in Ribeirao Preto, the new research brings interesting discussion, but the data presented are still not related to T. Rex’s “Tripartition” is not enough to set up.
“You need to look at these samples more carefully and go beyond femur strength and teething differences,” he says.
“In any case, the analyzes are important to draw attention to the ecological niche occupied by tyrannosaurs, which may have varied during their evolutionary history and during the development of individuals throughout life, with smaller and smaller animals being different than adults. -Catch different prey, for example.”