Specialists at the Ernesto Bachmann Paleontological Museum in Neuquén, Argentina, have discovered a new species of dinosaur whose anatomy also featured the “little arms” popularized by the T-Rex. This species has been named ” Meraxes gigas”.
Interestingly, despite belonging to the same major biological group, Tyrannosaurus and Meraxes evolved independently, but developed similar traits – so the new dinosaur also bore the “T-Rex arms” (which reads “small T- Rex”, they have nothing: each arm could lift between 90 and 100 kg).
“The Fossil of M. gigas shows detailed, complete, and never-before-seen regions of the skeleton, such as the arms and legs, which have helped us understand some of the evolutionary trends and anatomy of Carcharodontosaurids — the group to which the M. gigas“, said Juan Canale, excavation project manager.
The experts who sign a study on the new species guarantee it, however: although they are similar, the two dinosaurs are quite distinct. O M. gigas died out about 20 million years before the birth of Tyrannosaurus, and the similarity between one dinosaur and another compared to “small T-Rex arms” was an advantageous but unrelated evolution.
“I am convinced that these disproportionately light weapons had some sort of function,” Canale said. “The skeleton shows large muscle attachments and a fully developed pectoral collar, so the arms had strong muscles. In practice, it’s not as if these limbs are useless to animals, but rather that their exact function has not yet been exactly determined by research.
Of course, we are not talking about hunting: previous studies have already stipulated that the larger the head of one of these animals, the smaller the arms. As Tyrannosaurus and Meraxes had multiple bone mechanisms in the jaw and extremely strong muscles in the neck, all the predation part was done through the head.
Canale speculates that, like tyrannosaurus, meraxes used their arms to hold females of their species during mating or to find some sort of extra support for getting up when waking or falling.
The fossil found was quite complete, which allowed scientists to accurately identify more details about the animal: when it died, it was around 45 years old, measuring something almost 11 meters (m) in height. length (from nose to tail) and weighing more or less less than four tons (4,000 kg).
Moreover, the obvious distinction that it was an adult individual was the presence of small bumps – something like “horns” or “crowns” – on the forehead and around the eyes.
Canale believes these facial details served as an attraction to catch the attention of females of the species, but since direct observation is impossible, he said he was excited to continue studying the fossil, which he says he is in “priceless shape”.
The full study was published in the scientific journal Current biology.
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