(pronounced /ˌdʒaɪɡəˌnoʊtəˈsɔrəs/ JYE-gə-NOH-tə-SOR-əs) is a genus of carcharodontosaurid dinosaur that lived around 97 million years ago during the early Cenomanian stage of the Late Cretaceous Period. It is one of the largest known terrestrial carnivores, slightly larger than Tyrannosaurus, but smaller than Spinosaurus. Its fossils have been found in Argentina.
Discovery and speciesEdit
Size (in orange) compared with selected giant theropodsGiganotosaurus carolinii was named for Ruben Carolini, an amateur fossil hunter who, in 1993, discovered the fossils in deposits of Patagonia (southern Argentina) in what is now considered the Candeleros Formation. It was published by Rodolfo Coria and Leonardo Salgado in the journal Nature in 1995.
The holotype specimen's (MUCPv-Ch1) skeleton was about 70% complete and included the skull, pelvis, leg bones and most of the backbone. Various estimates find that it measured somewhere between 12.2 and 13 m (40 and 43 ft) in length, and between 6.5 and 13.3 tons in weight. A second, more fragmentary, specimen (MUCPv-95) has also been recovered. It is only known from a portion of the left dentary which is 8% larger than the equivalent bone from the holotype. This largest Giganotosaurus specimen is estimated to represent an individual with a skull length of 195 cm (6.40 ft), compared to the holotype's estimated at 1.80 m (5.9 ft) skull, making it likely that Giganotosaurus had the largest skull of any known theropod. Giganotosaurus surpassed Tyrannosaurus in mass by at least half a ton (the upper size estimate for T. rex is 9.1 t).
Giganotosaurus carolinii was slightly larger than Tyrannosaurus rex, but had a brain only about half as big as those of tyrannosaurids. The teeth of Tyrannosaurus were longer and wider, and more variable in size. The teeth of Giganotosaurus were shorter, less variable and narrower than those of Tyrannosaurus, and were more adapted for slicing flesh. A well-developed olfactory region means that it probably had a good sense of smell. Its skull, although large, had a slender build.
Titanosaur fossils have been recovered near the remains of Giganotosaurus, leading to speculation that these carnivores may have preyed on the giant herbivores. Fossils of related carcharodontosaurids grouped closely together may indicate pack hunting, a behavior that could possibly extend to Giganotosaurus itself.
Blanco and Mazzetta (2001) estimated that Giganotosaurus might have been capable of running at speeds up to 14 metres per second (50 km/h; 31 mph).
Artist's impressionGiganotosaurus, along with relatives like Tyrannotitan, Mapusaurus and Carcharodontosaurus, are members of the carnosaur family Carcharodontosauridae. Both Giganotosaurus and Mapusaurus have been placed in their own subfamily Giganotosaurinae by Coria and Currie in 2006 as more carcharodontosaurid dinosaurs are found and described, allowing interrelationships to be calculated.