Dinosaurs A to Z
Allosauroidea

Giganotosaurus carolinii JIG-uh-NOTE-oh-SOR-us

"Giant southern lizard"

Giganotosaurus silhouette
You 1.8 m (5.9 ft) tall
Giganotosaurus 13 m (41 ft) long
as long as 8 people standing fingertip to fingertip
silhouette · Ivan Iofrida (CC-BY) via PhyloPic
Length
13 m (41 ft) — About 12.5 m long, ~7 tonnes — slightly longer than T. rex.
Period
Late Cretaceous (99–97 Mya)
Place
South America · Argentina
Food
Carnivore — Large prey — possibly the giant titanosaur sauropods that lived alongside it.
Clade
Allosauroidea Dinosauria Saurischia Theropoda Big Jurassic-Cretaceous predators: Allosaurus, Carcharodontosaurus.

A "giant southern lizard" from Patagonia, rivalling T. rex for the title of largest land predator.

Giganotosaurus reconstruction by Nobu Tamura (http://spinops.blogspot.com)
Reconstruction · Nobu Tamura (http://spinops.blogspot.com) (CC-BY)

Giganotosaurus rivaled Tyrannosaurus rex in size — possibly even longer, though probably lighter. It lived 30 million years before T. rex on a different continent, hunting giant sauropods across what is now Patagonia. Its discovery in 1993 dethroned T. rex as the biggest carnivore, though new finds keep reshuffling the list.

More about Giganotosaurus

Discovery

Named by Rodolfo Coria and Leonardo Salgado · 1995 · the Candeleros Formation in the badlands near Villa El Chocon, Neuquen province, Patagonia, Argentina

In 1993 the amateur Argentine fossil hunter Ruben Carolini found the tibia (lower leg bone) of a theropod while driving a dune buggy in the badlands. Specialists from the National University of Comahue excavated the roughly 70% complete skeleton, and Coria and Salgado described it as the holotype in 1995.

The genus name means "giant southern lizard", from the Ancient Greek gigas ("giant"), notos ("austral/southern", a nod to where it lived), and sauros ("lizard"). The species name, carolinii, honors its discoverer, Ruben Carolini.

Ruben Carolini. Amateur Argentine fossil hunter who discovered the holotype tibia while driving a dune buggy in the badlands near Villa El Chocon in 1993; the species name carolinii honors him.

Was Giganotosaurus really bigger than Tyrannosaurus?
The honest answer is that we cannot be sure. Because the skeleton is incomplete, size depends heavily on how missing parts are reconstructed. Some researchers find it larger than Tyrannosaurus, while others find them roughly equal and judge the biggest estimates to be exaggerated.
For the curious → Was it warm-blooded, and what would that mean?
It is thought to have been homeothermic, a form of warm-bloodedness, with a metabolism somewhere between that of a mammal and a reptile. If so, that intermediate metabolism may have allowed it to grow quickly.

What we know

  • Skull longer than T. rex but more lightly built — about 1.6 m long.
  • Closely related to Carcharodontosaurus and Mapusaurus — the carcharodontosaur family.
  • Lived alongside the giant sauropod Andesaurus.
  • Multiple individuals found together at one site, possibly a pack.

What we guess

  • Whether Giganotosaurus or T. rex was heavier — estimates put both close to 7–8 tonnes.
  • Whether the multiple-individual site is real pack evidence or just multiple deaths over time.
  • How it brought down adult titanosaurs — slashing bites and exhaustion are the leading ideas.