Meraxes gigas, a new giant predatory dinosaur discovered in Patagonia, had arms as short as T. rex
In northern Patagonia, Argentine and American paleontologists discovered the remains of one of the largest carnivorous dinosaurs to date. With sturdy legs, small arms like the t rexhuge head and relative of the great Giganotosaurusthis new species, which lived more than 90 million years ago and was 11 meters long, expands the family of the greatest terrestrial hunters that ever existed: the carcharodontosaurids.
Giant carnivorous dinosaurs such as Tyrannosaurus rex and abelisaurids are characterized by having very small forelimbs that contrast with their enormous dimensions, massive skulls and walking, necessarily, on two hind legs.
The remains of Meraxes were found in Argentine Patagonia and were christened “the great dinosaur eater”
with dragon name
Investigation leader Juan Ignacio Canale is an avid reader of the fantasy saga. Song of Ice and Fire that gave rise to the series Game of thrones (Game of thrones). That’s why, when naming his most recent discovery in northern Argentine Patagonia, this paleontologist did not hesitate: he named it after one of the fantastic creations of the American writer George RR Martin.
“This is a new species of huge carnivorous dinosaur, 11 meters long, with small arms, a large skull and an estimated weight of 4,200 kg, which lived between 96 and 93 million years ago. Turn on Meraxes gigas, as one of dragons of novels”tells SINC the director of the Laboratory and Research Area of ‘Ernesto Bachmann’ Museum at Villa El Chocón, in the province of Neuquén (Argentina). “I liked how it sounded. I proposed this to the group and he stayed.”
4,000 kg and 11 meters long
Researchers discovered Meraxes in Patagonia in 2012 and have spent the last few years extracting, preparing and analyzing every bone in its skeleton. The dinosaur is part of the Carcharodontosauridae family, a group of giant carnivorous theropods that also includes Giganotosaurus, one of the largest known carnivorous dinosaurs and one of the reptilian stars from the movie “Jurassic World: Dominion”.
Although not the largest among carcharodontosaurids, Meraxes was still an imposing animal, measuring about 11 meters from snout to tail tip and weighing approximately 4,000 kg.
As his skull got bigger, his arms got smaller. Recreation of Meraxes giga skull. Credit: Jorge Gonzalez
The giant Meraxes was described in a article published in Current Biology.
When he died he was 45 years old, the specimen was about 11 meters long and weighed over four tons.
The researchers recovered Meraxes from rocks that are between 90 and 95 million years old, along with other dinosaurs, including several specimens of long-necked sauropods.
Meraxes is among the most complete carcharodontosaur skeletons that paleontologists have found so far in the southern hemisphere and includes nearly the entire skull, hips, and left and right arms and legs of the animal.
“The cool thing is that we found that the body design is surprisingly similar to that of tyrannosaurs like T. rex,” said Peter Makovicky, one of the study’s lead authors and a professor at the NH Winchell College of Earth and Environmental Sciences at the University of Minnesota. . . “But they’re not particularly related to T. rex. They are from very different branches of the carnivorous dinosaur family tree.
Why do these meat-eating dinosaurs get so big and have these tiny little arms?’
“The discovery of this new carcharodontosaurid, the most complete to date, gives us an excellent opportunity to learn about its systematics, paleobiology and real size like never before,” said Sebastián Apesteguía, co-author of the study and researcher at Maimónides University in Argentina.
Using statistical data provided by Meraxes, the researchers found that large megapredator dinosaurs from all three therapod families grew similarly. As they evolved, their skulls got bigger and their arms got progressively shorter.
The possible uses for the tiny forelimbs of T. rex and other large meat-eating dinosaurs have been the subject of much speculation and debate.
The arm is shortened so the skull is huge
“What we’re suggesting is that there is a different version of this,” Makovicky said. “We shouldn’t worry so much about using the arms, because in fact the arms are getting smaller as a result of the increase in the size of the skulls. Regardless of whether or not the arms are used, they are taking on a secondary role as the skull is being optimized to handle larger prey.”
The researchers also found that carcharodontosaurids, including species from Patagonia, evolved very quickly but suddenly disappeared from the fossil record shortly afterwards.
“Usually, when animals are on the brink of extinction, it’s because their rates of evolution are quite slow, which means they’re not adapting very quickly to their environment,” explained Juan Canale, lead author of the study and a researcher at the Universidad Nacional. . . of the Rio Negro. “Here we have evidence that Meraxes and their relatives evolved very quickly and yet after a few million years they disappeared and we don’t know why. It’s one of those discoveries where you answer some questions but raise more questions for the future.”