Giganotosaurus: Beast of the Week

This week we'll be checking out a giant carnivore that has been continuing to gain popularity since its discovery.  Make way for Giganotosaurus carolinii! 

Giganotosaurus was a meat-eating dinosaur that lived in what is now Argentina during the late Cretaceous period, between 99 and 97 million years ago. The genus name translates to "Giant Southern Lizard".  Giganotosaurus is famous for being one of the largest carnivorous dinosaurs known, the largest specimens estimated at about 41feet(12.5meters) long from snout to tail, based on known fossil material.  

Gigianotosaurus life reconstruction in watercolors by Christopher DiPiazza

Gignotosaurus was a member of the carcharodontosaurid family, a branch of carnivorous dinosaurs that flourished during most of the Cretaceous period as the dominant land predators until they were eventually replaced by tyrannosaurids in the northern hemisphere and abelisaurids in the southern hemisphere.  Carcharodontosaurids are characterized by having relatively long skulls that slightly taper towards the tip of the snout. Their jaws were lined with blade-like ,serrated teeth, which is how this group earned its name, the "shark-toothed lizards".  Acrocanthosaurus and Concavenator are two other members of this family that have been featured on Prehistoric Beast of the Week.  

Giganotosaurus had a huge skull that measures between five and six feet long. The surface above its snout and eyes was rough in texture, implying there was some sort of horn-like keratin material growing there in life.  This dinosaur probably had some kind of low crest on its head in life either for display within the species, or possibly for some sort of combat.  The teeth were blade-like and serrated, like those of a shark, and the jaws were long and laterally narrow.  The tip of the lower jaw jutted down a bit, forming a "chin".  It is thought that this "chin" could have added extra momentum if Giganotosaurus was making contact with the front of its jaws as it bit.

Giganotosaurus skeletal mount on display at the Fernbank Museum of Natural History in Georgia. (image credit: Johnathan Chen)

All these jaw features imply Giganotosaurus wasn't adapted for crushing bone with its jaws, but rather making fast slices through soft tissue.  This reflects a hunting strategy aimed at making the prey animal bleed to death with deep cuts, rather than paralyzing it with a crushing blow, like a Tyrannosaurus might.  This makes sense since Giganotosaurus would have shared its environment with several large species of sauropod dinosaurs, some of which were larger than Giganotosaurus, and all of them would have been slower, so the strategy of slicing hunks of flesh off over a longer period of time, causing severe bleeding, makes sense for hunting a prey item that was too large to be taken down in one powerful bite.

That is all for this week!  Feel free to comment below!

References

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

Coria, R. A.; Salgado, L. (1995). "A new giant carnivorous dinosaur from the Cretaceous of Patagonia". Nature. 377 (6546): 224–226.

Coria, R. A.; Currie, P. J. (2002). "The braincase of Giganotosaurus carolinii (Dinosauria: Theropoda) from the Upper Cretaceous of Argentina". Journal of Vertebrate Paleontology. 22(4): 802–811.

Leanza, H. A; Apesteguía, S.; Novas, F. E; de la Fuente, M. S (2004). "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages". Cretaceous Research. 25 (1): 61–87.

Novas, F. E.; Agnolín, F. L.; Ezcurra, M. D.; Porfiri, J.; Canale, J. I. (2013). "Evolution of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia". Cretaceous Research. 45: 174–215.

Therrien, F.; Henderson, D. M.; Ruff, C. B., 2005, "Bite Me: Biomechanical models of theropod mandibles and implications for feeding". In: Carpenter, K., The Carnivorous Dinosaurs. Life of the Past. Indiana University Press. pp. 179–237