Article by Rashmi Wickramasinge
Tyrannosaurus… who?
So far the world knew only about the T rex or Tyrannosaurus rex species of the dinosaur genus Tyrannosaurus. But the recent studies suggests that there are three different species of this fascinating reptiles. 🤔
Tyrannosaurus rex (T.rex) aka “king of the tyrant lizards” has roamed the earth 68 million years ago, scaring the daylights out of other living species. They owned a massive bulky body, strong jaws and sharp teeth. From the snout to the tip of the tail their length was about 40 feet. This carnivorous species had even preyed on one another. They had a strong sense of smell which helped to find their prey and mates. 😬😬
Do you know how much strong their bite force was? With they stiff skull, they could project all the force of the massive jaw muscles creating a 6 tons pressure. How perilous it could have been when this pressure was combined with 60 of eight inch-serrated teeth? They could even crush a car by biting without any struggle. 😯
They too had weaknesses!
Like all other creatures on the planet, these mighty creatures had weaknesses. Their arms were ridiculously small in proportion to their body. The use of arms is still in debate among the scientists. While some believe that the arms were adopted to slash and deeply wound the prey, others believe that the arms were used to hold a mate. Also, T-rex was not a fast runner. They could only run about 3.2km per hour. If they have moved faster than 3.2 km per hour their bones in their feet would have shattered.
The first fossil of T.rex was discovered in Hell Creek, Montana in 1902 by Barnum Brown. The excavations lasted for three years.
Three distinct species!! really? 😯
So far we have been talking about only the T rex, but the recent studies provide evidence that he had relatives. Scientist Gregory Paul and the team carried out a study on the bones and dental remains of some Tyrannosaurus specimens. Investigations were carried to measure the robustness; the strength of the bones. The robustness of 24 femur specimens were analysed. Moreover, the base of teeth and space in the gums were measured to determine whether the Tyrannosaurus had one slender incisor or two of them.
Analysis showed that some femurs were robust and some were gracile. Researchers claim that this significant difference in the strength of the femurs were not due to sex or the stage of growth.
The specimens used in the study where found in distinct layers of sediments
In the lower layer of sediments, only femurs that are robust were found. Since the robustness of the femurs of other theropod species in the same layer was not much different, it can be said that there was only one Tyrannosaurus existed in that period.
Only a gracile femur was found layer. Both gracile and robust femurs were found in the upper layer which is most recent layer. These findings prove that Tyrannosaurus was not just T rex but has developed into two distinct species.
Furthermore, the specimens from the lower and middle layers had two incisor teeth and more robust femurs. Another group of specimens from the middle and upper layers had one incisor tooth and more slender femurs.
Scientists have the coined the scientific name Tyrannosaurus imperator (tyrant lizard emperor) to denote the first species and Tyrannosaurus regina (tyrant lizard queen) to the second group.
And our well known T. rex in the Jurassic park movies; Tyrannosaurus rex (tyrant lizard king) had more robust femurs and one incisor tooth.