Discover a new giant carnivorous dinosaur with tiny weapons like T. rex

Miraxis Gegas – A new species of dinosaur has been discovered with disproportionately short arms, just like T-Rex Phone call Miraxis Gegas†

Dinosaurs (like the notorious) T-Rex) is not the only group of giant small-armed carnivorous dinosaurs. Paleontologists have even discovered a new species of dinosaur with completely disproportionately short arms like: T-Rex Phone call Miraxis Gegas† Results will be published in the journal current biology Today (7 July) he said: T-Rex and the M Gegas Developed to have fully autonomous small arms, it identified many potential functions of short arms, such as mating or locomotion assistance.

‘fossil’ M Gegas Never seen before, it shows entire parts of the skeleton, such as arms and legs that have helped us understand some of the evolutionary trends and anatomy of Carcharodontosaurids – the group that M Gegas This “belongs to” Juan Canal, project lead for the Ernesto Bachmann Museum of Paleontology in Neuquén, Argentina.

First, to make up for this, the authors say: T-Rex I didn’t get their short arms from M Gegas Or vice versa. Not only M Gegas It became extinct about 20 million years ago T-Rex They have become a species, but in the evolutionary tree they are also very far apart. “There is no direct relationship between them,” Kanal says. Instead, Kanal believes that having small arms provides dinosaurs some kind of survival advantage in some way.

I’m convinced that those relatively small arms have a job. The skeleton showed large muscle overhangs and fully developed Beck muscles, so the arm had strong muscles,” Kanal says. This shows that the arms did not contract because they were useless for dinosaurs. The more difficult question is what exactly were the functions.

From previous studies, the research group demonstrated that for dinosaurs such as: M Gegas and the T-RexThe larger their heads were, the smaller their arms became. It was certainly not useful for hunting, Kanal argues, because “acts associated with predation were most likely performed by the head”.

“I tend to think their arms were used for other types of activities,” Kanal says. From the fossil record, the team was able to paint a picture of this life M Gegas before you die. The dinosaur lived in the region of present-day northern Patagonia in Argentina and was 45 years old, about 11 meters long and weighed more than four tons. And she had a big family. “The group thrived and peaked in diversity shortly before its extinction,” Kanal says. “They may have used the arms for reproductive behaviour, such as holding the female during mating or supporting herself to lie down after a break or a fall,” Kanal added.

drilling site Miraxis Gegas† Credit: Juan I Channel

The team also found that the skull M Gegas It was decorated with combs, grooves, spurs and small horns. “These forms appear late in development as individuals mature,” Kanal says. The group believes that the features may have been used to attract potential partners. “Sexual selection is a powerful evolutionary force. But because we cannot directly observe their behavior, it is impossible to be sure.”

“The fossil has a lot of new information and it’s in excellent condition,” Canale said. He looks forward to exploring other questions he asks M Gegas Fossil can help him answer. “We found the perfect place on the first day of searching, and M Gegas “It was probably one of the most exciting points of my career,” Kanal says.

Reference: “New Giant Carnivorous Dinosaur Reveals Converging Evolutionary Trends in Arm Reducing Theropod” by Juan I. Canal, Sebastian Apisteguia, Pablo A. Galena, Jonathan Mitchell, Nathan D. Smith, Thomas M. Colin, Akiko Shinya, Alejandro Halusa, Federico Giancini, Peter J. Makovsky, July 7, 2022, Available here. current biology†
DOI: 10.1016 / j.cub.2022.05.057

This work was supported by the US National Science Foundation and the National Geographic Society.