WASHINGTON — A study proclaims a newly named species the heavyweight champion of all dinosaurs, making the scary Tyrannosaurus rex look like a munchkin.

The 76-ton dinosaur’s fossils were found in southern Argentina in 2012. Researchers who examined and dated them said the long-necked creature was the biggest of a group of large dinosaurs called titanosaurs.

“There was one small part of the family that went crazy on size,” said Diego Pol of the Egidio Feruglio paleontology museum in Argentina, co-author of the study published Tuesday in the journal Proceedings of the Royal Society B.

The researchers named the dinosaur Patagotitan mayorum after the Patagonia region where it was found and the Greek word titan, which means large. The second name honors a ranch family that hosted the researchers.