The Giganotosaurus was a large dinosaur that existed on the earth in the late Cretaceous period. It was a carnivorous dinosaur belonging to suborder Theropoda. This reptile is the largest known meat eating dinosaur of South America, definitively rivaled only by the Egyptian Spinosaurus. It is distantly related to the famous North American Tyrannosaurus, and is more closely related to the Carcharodontosaurus.
The time period of the existence of the Giganotosaurus was about 100 to 94 million years ago. This lies in the Cenomanian and Turonian ages. This age preceded the Maastrichtian age by about 30 million years, the phase during which the Tyrannosaurus walked the earth. Incidentally, the timeline of the Giganotosaurus matches with that of the Carcharodontosaurus, with the latter being found in Northern Africa.
The size of the Giganotosaurus is estimated to be a little more than 13 meters. Some scientists posit that it could have grown to slightly larger lengths as well. Its weight is estimated to be between 7 and 14 tons. Its braincase was much smaller proportionately as compared to other theropods, raising many questions about the intelligence levels of the dinosaur. It was bipedal, and had a hunched over posture like the other large theropods.
Discovery of fossils
The remains of the Giganotosaurus were discovered in Patagonia, Argentina, in region that is classifies as the Candeleros Formation.
They were found by Ruben Dario Carolini in the year 1993. Carolini was a novice fossil hunter and stumbled upon the remains while perusing the southern Argentinian lands.
The holotype consisted of a partial skull, the spinal column, the pectoral and pelvic girdles and the hind legs and tail. The forelimbs were conspicuously absent.
After these remains were described, it was found that a mandibular fossil found in 1988 by Jorge Calvo also belonged to the Giganotosaurus. It was about 8 % percent larger than the comparable fragment of the holotype.
A complete Giganotosaurus skeleton has not yet been discovered.
The Giganotosaurus is classified under suborder Theropoda, clade Carnosauria, family Carcharodontosauridae and tribe Giganotosaurini. It is clear that the Carcharodontosaurus is the type genus for family Carcharodontosauridae, but the type genus for the tribe Giganotosaurini is the Giganotosaurus. This tribe contains the Tyrannotitan and the Mapusaurus.
This placement of the Giganotosaurus within family Giganotosauridae was suggested by Novas in 2013.
The size of the skull of the Giganotosaurus has been a matter of contention among scientists, since a complete skull has not yet been ascribed to the dinosaur.
Upon first observation, the skull was estimated to be around 6 feet in length. But Salgado and Coria later revised this figure to about 5 feet. The former size would make it much larger than the Tyrannosaurus.
The skull was slender and elongated.
Based upon the size of the jaws and their muscle attachments, paleontologist have estimated that the bite force of the Giganotosaurus was about one third that of the Tyrannosaurus. This means that it relied on cutting and slicing its prey as opposed to overpowering it based on sheer strength.
Although the endocast of the skull was larger in volume as compared to the Carcharodontosaurus, its cranial capacity was comparable, reinforcing the facts that the carcharodontosaurids had smaller brains than the Tyrannosaurids.
The physical characteristics
The Giganotosaurus was one of the largest carnivorous dinosaur to ever inhabit the earth. It is believed to be larger and longer than the Tyrannosaurus and about the same size as the Carcharodontosaurus, if not larger.
Its adult length was about 42 to 43 feet from snout to tail. Its weight was 7000 to 15,000 kilos. In the absence of a complete skeleton, these values are calculated estimates.
The forearms of the Giganotosaurus have not yet been discovered, but based upon the structure of its shoulder girdle, scientists believe they were highly reduced in size, but so much as the Tyrannosaurus.
The hind limbs of this dinosaur were much better adapted for running than those of the Tyrannosaurus. It is judged that the Giganotosaurus could spirit at a maximum speed of 15 meters per second while the latter likely could not run beyond 10 meters per second without compromising stability.
The tail of this dinosaur was long and muscular like that of other carcharodontosaurids.
Habits and habitat
The Giganotosaurus was terrestrial dinosaur that walked on its hind legs. Although it could not stand erect, the anterior orientation of its femoral head suggests that it could stand slightly straighter as compared to the Tyrannosaurids.
It is believed that the Giganotosaurus hunted the large sauropods of South America. Fossils of the Andesaurus were found in close association with it. Since its bite force was weaker than some of its contemporaries, scientists believe that it either hunted upon the young ones of these dinosaurs or engaged in guerrilla warfare with the adults. It could inflict serious injuries to the limbs of the theropods and wait for them to die of blood loss or infection.
As the Mapusaurus is believed to have hunted in herds, some paleontologists speculated that the Giganotosaurus could have too. A packs of Giganotosaurus dinosaurs could even have taken down an Argentinosaurus.
The habitat of this dinosaur consisted of lush woodlands and plains, along with perennial rivers and swamps.
Related and coexisting species
The Giganotosaurus is related to the Carcharodontosaurus, Tyrannotitan and the Mapusaurus. It possibly shared its habitat with the Andesaurus, Limaysaurus, Ekrixinatosaurus and even the Argentinosaurus.
The concluding notes
The Giganotosaurus is the largest known carnivore of South America and was one of the fiercest predators of its time. If it indeed did hunt in packs, there is no known creature that it could not subdue. The only threat that it could possibly have had in its environment was other large theropods.