A team of scientists in Argentina says they have discovered a new species of predatory dinosaur, with a giant head but very small arms for its size. The discovery could help unravel why the famous Tyrannosaurus Rex has short arms.
In an article in the academic journal Current Biology, scientists say that skeletal remains of the new, previously unknown dinosaur were found in northern Patagonia.
Nicknamed Meraxes gigas, he was 11 meters long, with a skull measuring 1.2 meters, but arms measuring just 60.9 centimeters. Scientists believe that the short arms gave this carnivorous animal advantages to survive.
“I’m convinced that these proportionately smaller arms had some sort of functionality. The skeleton shows large muscle attachments and fully developed pectoral structures, so the arms had strong muscles,” said Juan Canale, lead author of the study.
“They may have used their arms for reproductive behavior, to hold the female during coitus or as support to get up off the ground after a rest or a fall,” he added.
Peter Makovicky, co-author of the study, said the dinosaur’s arms were “literally half the length of its skull and the animal would not have been able to reach its mouth” with its hands.
Makovicky says he believes the huge head of this species was the main predatory instrument, taking over the functions that the arms played in smaller dinosaurs.