A group of scientists in Argentina believe they have discovered a new predatory giant dinosaur with a very large head but small arms for its size.
Scientists writing in the journal Current Biology about the discovery state that the skeletal remains of a previously unknown species were unearthed in Northern Patagonia.
The 11-metre-tall dinosaur, called Meraxes gigas, had a skull 1.2 meters but arms only 60 cm long.
Scientists believe the small limbs gave the carnivorous dinosaur survival advantages.
“I think these proportionally small arms have some kind of function. The skeleton shows large muscle inserts and fully developed chest girdles, so there were strong muscles in the arms,” says Juan Canale, author of the study.
“They may have used their arms to hold the female during mating or as support when she got up after she fell.”
The study’s co-author, Peter Makovicky, notes that the dinosaur’s arms were “literally half the length of the skull and did not extend all the way to the muzzle.”
The species’ giant head is the main predatory tool, taking over the functions that arms in smaller species do, Makovicky says.
Named after a fictional dragon in the Game of Thrones book series, Meraxes gigas belongs to the shark-toothed lizard family.
These four-ton reptiles are believed to have lived 90-100 million years ago.
Scientists say tyrannosoroids (tyrant lizards) and abelisoroids (Abel lizards) develop small arms for similar reasons.