Until the mid-1990s, it was generally thought that Tyrannosaurus was the largest land predator ever. Then, scientists discovered Giganotosaurus which lived was a 45 feet (13.8 meter) long carnivore that lived in Argentina about 100 million years ago. New research, first published in 2006, now suggests that Spinosaurus may have been even larger still: upto 51 feet (17 meters) long.