Giganotosaurus

Giganotosaurus ("giant southern lizard" ) was a theropod dinosaur from the Cretaceous of Argentina. It is one of the largest theropod dinosaurs known.

Description
The length of the holotype specimen is estimated to be around 12 to 13 meters, and its weight is estimated at 6.5 to 13 tons. This is slightly larger than the largest known Tyrannosaurus (by weight and possibly by length) and only slightly smaller than Spinosaurus. The same holotype had a skull estimated to be 1.8 meters long, the largest skull of any theropod discovered thus far. Another specimen has a fragmentary skull that is estimated to be even larger, at 1.95 meters.

Giganotosaurus is often compared to Tyrannosaurus, but there are notable differences apart from size. The brain of Giganotosaurus was smaller than that of Tyrannosaurus, and its teeth were more adapted for slicing instead of crushing.

Classification
Giganotosaurus is classified as a carcharodontosaurid carnosaur, most closely related to Mapusaurus.

Discovery
Giganotosaurus was first discovered in the Neuquén province of Argentina by Rubén Dario Carolini, an amateur fossil hunter. The discovery was officially reported in 1994, and later described in 1995 by Leonardo Salgado and Rodolfo Coria. It was named Giganotosaurus carolinii, honoring the original discoverer.

Paleoecology
Giganotosaurus shared its environment with several species of large sauropod, as well as many other dinosaurs and small animals.

Pack hunting
Several specimens of a close relative of Giganotosaurus, Mapusaurus, have been found fossilized together, which may indicate that they lived together and possibly hunted in packs. The same may be true for Giganotosaurus, and it has indeed been portrayed in several television programs hunting in packs.