Giganotosaurus ("giant southern lizard") is currently one of the largest known meat-eating dinosaur ever. For many years Tyrannosaurus held that record (although bits and pieces of Carcharodontosaurus and Spinosaurus showed that they were as large as any individual T. rex). Then, in 1995, paleontologists Rodolfo Coria and Leonardo Salgado reported the discovery of a new meat-eater bigger than any tyrant lizard. They named the giant dinosaur, Giganotosaurus carolini.
Bone for bone, it was larger than the largest skeleton of T. rex ever found! The skull alone was 5 feet (1.5 m) long! What's more, a lower jaw bone was later found from an individual even bigger than the first one - with a skull perhaps 1.5 meters (5 feet) long. Clearly, Giganotosaurus was a gigantic dinosaur.
When Giganotosaurus was alive, the most common plant-eaters in South America were the titanosaur sauropods. While a single Giganotosaurus could kill a young titanosaur, it would take many Giganotosauruses to bring down a giant adult. Originally, there was no evidence that Giganotosaurus hunted in groups, but a recent discovery from slightly younger rocks shows that they indeed may have lived in packs of 6-12 or more individuals.
Genetic material of Gigantosaurus was in possession of InGen by the year 2014 and was used in the creation of the genetic hybrid Indominus rex.