Terrific Tetanurae! #6 Giganotosaurus carolinii

This is part 2 of a series on Giganotosaurini. For part one, click here.

During the Cretaceous, the biodiversity of the clade of theropods known as Tetanurae skyrocketed, with new families, such as the dromeosaurids, becoming very successful. The Cretaceous period was also a time of giant herbivorous dinosaurs, and those dinosaurs were preyed on by some of the most amazing killers in all of Earth’s history.  Among these predators were the carcharodontosaurids, a diverse group of large bodied, large skulled allosauroids, the remains of which are found throughout the southern hemisphere. The carcharodontosaurids reached their apex in Giganotosaurus , a highly derived Giganotosaurinine carcharodontosaurid from the Cenomanian stage of the Cretaceous of Argentina.

Giganotosaurus was a huge predator, with size estimates placing it at around 41-45 feet in length and at around 6.5-13.8 tons in weight. Only 2 specimens of Giganotosaurus are known, and both have been attributed to G. carolinii. The holotype of G. carolinni is around 70% complete and was described in 1995 by Rodolfo Coria and Leonardo Salgado in 1995. A second specimen which consists of a partial lower jaw was attributed to G. carolinii by Jorge Calvo and Rodolfo Coria in 1998. This specimen may have come from an individual 8% larger then the holotype, but then again, the individual this specimen belonged to may have just had a deeper dentary. At the time of its discovery, Giganotosaurus carolinii was considered to be the largest land predator ever, but more recent analyses place the holotype at around the same length as the largest Tyrannosaurus rex specimen, Sue. Scott Hartman’s analysis placed the mass of the holotype of G. carolinii at slightly less then the mass of Sue, but he also stated, “To be fair, there’s only one good specimen of Giganotosaurus, and it took most of a century to find Sue, so it’s certainly possible that as additional specimens are collected we will find larger southern giants. As always, please remember we don’t have a statistically valid population of specimens from any of these large dinosaurs, so we are only comparing individuals, not species” .Nevertheless, G. carolinii was a huge predator and definitely would have been one of the main predators in its ecosystem, and the second specimen may indicate that some individuals of Giganotosaurus could achieve masses larger then those of the largest Tyrannosaurus. For more on the ecosystem Giganotosaurus lived in, go here.

Giganotosaurus (foreground) rests in the antediluvian plains of the Candeleros Formation while Andesaurus browses in the background.  Illustration by the author.  Colored pencils on paper, 2015.

Giganotosaurus (foreground) rests in the antediluvian plains of the Candeleros Formation while Andesaurus browses in the background.
Illustration by the author.
Colored pencils on paper, 2015.

Overall,  the discovery of Giganotosaurus carolinii revealed to the world that many Tetanurans could and did achieve immense sizes like Tyrannosaurus.

Sorry T. rex, you've just been dethroned!  Sue the Tyrannosaurus rex. Photo by the author, 2014.

Sorry T. rex, you’ve just been dethroned!
Sue the Tyrannosaurus rex. Photo by the author, 2014.

I hope you enjoyed the article, and thanks for reading! 

References

1. Coria, R.A. and Currie, P.J. .2002. “Braincase of Giganotosaurus carolinii (Dinosauria: Theropoda) from the Upper Cretaceous of Argentina.” Journal of Vertebrate Paleontology 22(4): 802-811.

2. “Mass estimates: North vs South redux” Scott Hartman. Scott Hartman’s Skeletal Drawing. com. October 26, 2013.

3. J.O. Calvo.1990. “Un gigantesco theropodo del Miembro Candeleros (Albiano–Cenomaniano) del la Formación Río Limay, Patagonia, Argentina”, VII Jornadas Argentinas de Paleontología de Vertebrados. Ameghiniana 26(3-4): 241

4. Calvo, J.O. and Coria, R.A. .1998. “New specimen of Giganotosaurus carolinii (Coria & Salgado, 1995), supports it as the largest theropod ever found.” Gaia 15: 117–122.

5. Coria, R.A. & Salgado, L. .1995. “A new giant carnivorous dinosaur from the Cretaceous of Patagonia.” Nature 377: 225-226.

6. Coria, R.A. and Currie, P.J. .2006. “A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina.” Geodiversitas 28(1): 71-118.

7. Holtz, Thomas R. Jr. .2012. “Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages”  Appendix.

8. Seebacher, F. .2001. “A new method to calculate allometric length-mass relationships of dinosaurs”. Journal of Vertebrate Paleontology 21 (1): 51–60.

9. Therrien, F.; Henderson, D.M. .2007. “My theropod is bigger than yours…or not: estimating body size from skull length in theropods”. Journal of Vertebrate Paleontology 27 (1): 108–115. 

10. Novas, F. E.; Agnolín, F. L.; Ezcurra, M. N. D.; Porfiri, J.; Canale, J. I. .2013. “Evolution of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia”. Cretaceous Research 45: 174.

11. R.A. Coria and L. Sagado. .1994. “A giant theropod from the middle Cretaceous of Patagonia, Argentina”, Journal of Vertebrate Paleontology 14(3, supplement):22A

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