The species Giganotosaurus were huge land-dwelling carnivores that roamed ancient Patagonia. They were the race of dinosaurs that ruled the land before tyrannosaurs took their throne. Recent finds from eastern Utah show that the shark-toothed dinosaurs actually held the tyrannosaurs back. For millions of years, it is thought that the tyrannosaurs were the largest-dwelling carnivores, but it seems Giganotosaurus were the more dominant species, as Discover magazine details:
“There was nothing inevitable about the rise of tyrannosaurs,” Brusatte says. In fact, it seems that the carcharodontosaurs held them back.
“It seems like tyrannosaurs exploded to huge size only after the carcharodontosaurs went extinct, or became much less common,” Brusatte says.
The dominance of the carcharodontosaurs may have also limited the expansion of tyrannosaurs into the Southern Hemisphere. To date, the only evidence of these tyrants below the equator is a questionable fossil from Australia. It may be, Cuesta says, that carcharodontosaurs and other large predators — such as the strange, horned abelisaurids — may have prevented tyrannosaurs from gaining a claw hold. The picture may change with new finds. “The fossil record is annoyingly patchy and incomplete,” Cuesta says, but the current pattern indicates that tyrannosaurs required other large carnivores to get out of the way before they could take over that role between 80 million and 66 million years ago.
image via Discover magazine