Newer estimates rank it at around 13 metres and 7.3 tons. This larger Giganotosaurus specimen was estimated to represent an individual 13.2 meters (43 feet) long that was about 3.7 meters (12.1 feet) tall at the hips and weighed about 8.2 tonnes (9 tons). A second specimen (MUCPv-95), was estimated at 6,5–8% larger. It is estimated at about 6.8 tonnes (7.5 tons) in weight, 3.48 meters (11.4 feet) tall at the hips, and 12.4 meters (41 feet) in length. The holotype specimen's (MUCPv-Ch1) skeleton was about 70% complete and included the skull, pelvis, leg bones, and most of the backbone. It was published by Rodolfo Coria and Leonardo Selgado in the journal Nature in 1995. Giganotosaurus carolinii was named after Ruben Carolini, an amateur fossil hunter, who discovered the fossils in the deposits of the Rio Limay Formation of Patagonia, southern Argentina, in 1993. It appeared superficially similar to other Carcharodontosaurs such as Carcharodontosaurus.

The Giganotosaurus means 'the giant southern lizard', as the Megalosaurus was the 'giant lizard'. The genus attracted much interest and became part of a scientific debate about the maximum sizes of theropod dinosaurs. A dentary bone, a tooth and some tracks, discovered before the holotype, were later assigned to this animal. The animal was named Giganotosaurus carolinii in 1995 the genus name translates as 'giant southern lizard' and the specific name honors the discoverer, Rubén D. The holotype was discovered in the Candeleros Formation of Patagonia in 1993, and is about 70% complete. Giganotosaurus (meaning 'giant southern lizard') is an extinct genus of Carcharodontosaurid theropod dinosaurs that lived in the Cenomanian of Argentina 99.6 - 97 mya. An artist's illustration of Giganotosaurus caroliniiĪ small theropod picks scraps from the open mouth of a Giganotosaurus individual.

Giganotosaurus jurassic world evolution