Meraxes, named after a fictional dragon from the Game of Thrones book series, was excavated over four years during field expeditions to the northern region of Argentine Patagonia, beginning with the skull found in 2012. .
Paleontologists said Thursday they had discovered a new species of giant carnivorous dinosaur that had a huge head and small arms, just like the Tyrannosaurus rex.
The researchers’ findings, published in the journal Current biologysuggest that the small forelimbs were not an evolutionary accident, but gave certain survival advantages to predators of the time.
Meraxes gigas, named after a fictional dragon from the Game of Thrones book series, was unearthed over four years during field expeditions to the northern region of Argentine Patagonia, beginning with the skull that was found in 2012.
“We won the lottery and found it literally the first morning,” lead author Peter Makovicky of the University of Minnesota told AFP.
The fossilized remains were remarkably well preserved. The skull is just over four feet long (127 centimeters), while the whole animal would have been about 36 feet long and weighed four metric tons.
His arms were two feet long, “so he’s literally half the length of his skull and the animal couldn’t have reached his mouth,” Makovicky said.
T. rex did not get his small arms from M. gigas. The latter became extinct 20 million years before the former emerged, and the two species were far apart in the evolutionary tree.
This image shows the transport of a plaster jacket from a new dinosaur Meraxes gigas, in the Las Campanas Canyon, 25 km southwest of Villa El Chocon, Neuquén Province, Argentina, on March 17, 2014.
In contrast, the authors believe that the fact that tyrannosaurids, carcharodontosaurids (the group to which Meraxes belonged) and a third species of giant predator called abelisaurids evolved all tiny arms points to certain benefits.
Makovicky believes that as its heads grew, it became the dominant tool in its predatory arsenal, assuming the role that the forelimbs would have had in smaller species.
Its co-author Juan Canale, responsible for the project at the Ernesto Bachmann Paleontological Museum in Neuquen, Argentina, went further by suggesting other advantages.
Pairing and movement support
“I’m convinced those proportionately tiny arms had some kind of function. The skeleton shows large muscle insertions and fully developed pectoral fissures, so the arm had strong muscles,” he said in a statement.
“They may have used their arms for reproductive behavior, such as holding the female during mating or leaning to get up after a break or fall.”
This image shows the excavation site of a new dinosaur, Gera Meraxes, in the Las Campanas Canyon, 25 km southwest of Villa El Chocon, Neuquen Province, Argentina, on March 15, 2014.
Meraxes traveled the Earth between 90 and 100 million years ago during the Cretaceous, at a time when the region was wetter, more wooded and much closer to the sea, Makovicky said.
They are said to have preyed on a number of contemporary sauropods, some of which were discovered at the same site.
The individual lived about 40 years, a mature old age for dinosaurs, and his skull was full of ridges, furrows, bumps, and small horns.
“It certainly would have looked very imposing and gargoyle-like,” Makovicky said.
“These are the types of traits that in live animals are often under sexual selection,” speculating that the species used its massive skulls as “advertising posters” to advertise potential mates.
New giant carnivorous dinosaur discovered with tiny arms like the T. rex More information: Juan I. Canale, The new giant carnivorous dinosaur reveals converging evolutionary trends in the reduction of the arm of theropods, Current biology (2022). DOI: 10.1016 / j.cub.2022.05.057. www.cell.com/current-biology/f… 0960-9822 (22) 00860-0
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Citation: New predator of giant dinosaurs discovered with tiny arms, such as T. rex (2022, July 10) recovered on July 10, 2022
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