(ORDO NEWS) — For a long time, scientists could not understand why many carnivorous dinosaurs needed their tiny forelimbs.
Now we may be able to answer this question – thanks to the discovery of a large carnivorous dinosaur that lived in Argentina 30 million years before the appearance of the tyrannosaurus rex.
The tiny forelimbs of Tyrannosaurus rex have long been the subject of numerous jokes and headaches for paleontologists who could not come up with a reasonable enough explanation for these “useless” limbs.
Helping to get up from the ground, holding a resisting victim, or even scratching the belly – a wide variety of functions were attributed to tiny “paws”.
Now we can say with confidence that the evolutionary tendency to reduce the forelimbs was not only a “chip” of tyrannosaurs and their closest relatives.
30 million years before the appearance of the “King of the Dinosaurs,” the same feature was observed in a completely different evolutionary line of carnivorous dinosaurs that diverged from the ancestors of the Tyrannosaurus rex at least 175 million years ago.
This discovery was made thanks to the discovery of an amazingly well-preserved skeleton in Patagonia, dug up back in 2012.
It took ten years for scientists to properly study the found sample and give it a complete description: it is now known that these bones belonged to a new species of predatory dinosaurs, called the giant meraxes ( Meraxes gigas ) – in honor of the dragon from the book cycle “A Song of Ice and Fire” by George Martin.
Meraxes belonged to the carcharodontosaurid family , giant carnivorous dinosaurs that included some of the largest terrestrial predators ever to roam our planet.
The new species cannot be called a champion: it was about 11 meters long and almost four tons in weight, but still it was a huge animal, which is the reason for the species name “giant”.
Most importantly, Meraxes had well-preserved forelimbs, thanks to which paleontologists, in particular, were able to establish that their length was only 47 percent of the length of the femur.
A similar situation was observed in abelisaurids and late tyrannosaurids. This means that the reduction of the forelimbs independently occurred in at least three evolutionary lines of carnivorous dinosaurs.
Parallel to this, dinosaurs had enlarged skulls, which not only allowed them to hunt ever larger prey, but also may have attracted opposite-sex mates during the mating season.
So, probably, the front legs of these animals did not have any special function: they simply decreased in order to lighten the front part of the body and allow the lizard to increase its head – its main tool when hunting large prey.
Another curious feature of Meraxes was the age of the animal at the time of death: after analyzing the structure of its bones, scientists came to the conclusion that the dinosaur was from 39 to 53 years old, which makes it one of the oldest dinosaurs found in general.
For comparison, the oldest tyrannosaurus found, nicknamed Trix , at the time of death was a little over 30 years old – and she (it is assumed that this is a female) already suffered from many diseases, including age-related ones.
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