About Giganotosaurus
| Scientific Name (Genus) | Giganotosaurus |
| Meaning of Name |
Giant southern lizard
Gigas (giant) [Greek] - notos (southern) [Greek] - saurus (lizard) [Greek] |
| Classification | Saurischia, Theropoda ( Carcharodontosauridae ) |
| Total Length | Approx. 12.2m - 13.5m |
| Diet | Carnivorous |
| Period | Early to Late Cretaceous |
| Sub-classification / Species Name | Giganotosaurus carolinii |
| Year of Paper Publication | 1995 |
| Genus Name Publication |
A new giant carnivorous dinosaur from the Cretaceous of Patagonia.
Nature, Volume 377. by Coria, Rodolfo A.; Salgado, Leonardo. 1995. |
Characteristics: Comparison with Tyrannosaurus and Unique Evolution
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Giganotosaurus is one of the largest carnivorous dinosaurs in history. Its size is often compared to the famous Tyrannosaurus rex, and it is highly likely that Giganotosaurus was equal to or slightly longer in total length. However, their body builds were significantly different.
While Tyrannosaurus was a "heavyweight" with a broad, barrel-like chest and thick legs, Giganotosaurus grew to a massive size while maintaining a slender and lithe body build rather than maximizing its weight. In the South American continent, it is thought to have evolved with an emphasis on agility and efficiency rather than overpowering with immense muscular strength.
Furthermore, fossils of a recently discovered close relative, "Meraxes," reveal that Giganotosaurus also had extremely reduced and short forelimbs (arms). Despite being of a completely different lineage from Tyrannosaurs, as their heads grew larger to become their primary weapons for predation, a common change (convergent evolution) occurred where their arms became smaller to maintain balance.
There was a time when it was thought that dinosaurs continued to grow infinitely until they died, like modern reptiles. However, examining the bone tissue of Giganotosaurus confirms a growth arrest sign called the "External Fundamental System." This indicates that the fossils found are not young individuals still growing, but fully grown, maximum-sized old individuals of their species.
Skull Structure and Sensory Organs
The skull of Giganotosaurus was very long, reaching approximately 1.6 to 1.8 meters. While Tyrannosaurus had powerful teeth capable of crushing bone, Giganotosaurus had relatively weak bite force and instead possessed thin, sharp, "steak knife"-like teeth. They were specialized in slicing flesh rather than crushing hard bones.
Based on the latest fossil analysis, a hypothesis has been proposed that the cheeks of dinosaurs contained strong ligament or muscle-like tissues called "Exoparia". In the case of Giganotosaurus, it is thought to have played a role in protecting the jaw joints from the twisting and impact forces applied when slicing through the flesh of prey.
Furthermore, CT scans of the brain cavity (braincase) inside the skull revealed that it had enormous olfactory bulbs. This indicates that they relied on their excellent sense of smell to search for prey and carrion across vast environments. Additionally, examining the orientation of the semicircular canals in the inner ear revealed that they typically held their snouts tilted downwards about 30 degrees from horizontal. It is presumed that this base posture was optimal for avoiding obstacles at their feet and stereoscopically measuring the distance to their prey.
Hunting Methods and Ecology
Regarding the walking speed and athletic ability of Giganotosaurus, there was once a theory that it could run at about 50 kilometers per hour (14 meters per second). However, current biomechanical research suggests that running in a way where both feet leave the ground while supporting a massive body of over 8 tons would pose an unacceptably high risk of bone fractures. Therefore, it is highly likely that their actual movement was limited to a "fast walk" like modern elephants, and their style was more suited to charging short distances from an ambush rather than chasing over long distances.
When hunting, Giganotosaurus utilized its wide-opening mouth to employ a "slash-and-dash" tactic, biting into its prey and quickly pulling away. Using its sharp, serrated teeth, it inflicted fatal lacerations on giant herbivorous dinosaurs and waited for them to bleed out and weaken.
Furthermore, a dinosaur extremely closely related to Giganotosaurus, Mapusaurus, has been found in a bonebed (a dense accumulation of fossils) containing multiple individuals ranging from juveniles to adults. This suggests the possibility that Giganotosaurus, too, did not hunt alone but cooperated in packs to hunt massive herbivorous dinosaurs.
Dinosaurs of the African and South American Continents
Giganotosaurus belongs to the family Carcharodontosauridae within the superfamily Allosauroidea. Its skull shares more characteristics with Carcharodontosaurus of the African continent than with Tyrannosaurus of North America.
The close relationship between the African dinosaur Carcharodontosaurus and the South American dinosaur Giganotosaurus serves as supporting evidence that both continents were connected by land until a relatively late period.
Discovery and Paper Publication
In 1993, Rubén D. Carolini, an amateur fossil hunter, found a fossilized tibia in the Candeleros Formation, a badland near Villa El Chocón in Neuquén Province, Patagonia, Argentina. Upon receiving the report of the fossil discovery, Argentine paleontologists Rodolfo Coria and Leonardo Salgado were dispatched to the site in 1994 to investigate.
Approximately 70% of the skeleton was preserved, and they excavated the vertebral column, rib cage, pelvis, femur, and more. These fossils were cataloged under the specimen number MUCPv-Ch1.
In 1995, Coria and Salgado described it as a new genus and species, Giganotosaurus carolinii. The genus name "Giganotosaurus" means giant southern lizard, and the species name "carolinii" honors its discoverer. Specimen MUCPv-Ch1 is housed and exhibited at the Ernesto Bachmann Palaeontological Museum, built near the discovery site, according to the wishes of the discoverer, Carolini.
Giganotosaurus Stamp and Fossil Gallery
