Giganotosaurus

Giganotosaurus (/ˌɡɪɡəˌnoʊtəˈsɔːrəs/ GIG-ə-NOH-tə-SOR-əs) is a genus of large theropod dinosaur that lived in what is now Argentina, during the early Cenomanian age of the Late Cretaceous period, about 100 to 95 million years ago. It was one of the largest known land carnivores. It could grow up to 13 meters (about 43 feet) long and weigh as much as 13 tons. This giant had a strong body, powerful jaws, and sharp teeth, making it a top hunter.

The holotype specimen of Giganotosaurus was found in the Candeleros Formation of Patagonia in 1993. It was named Giganotosaurus carolinii in 1995. The name means "giant southern lizard" and honors the discoverer, Ruben Carolini. Scientists think Giganotosaurus was the top hunter in its home, likely catching large animals such as young sauropod dinosaurs. It belonged to the family Carcharodontosauridae and was closely related to other big theropods like Mapusaurus, Tyrannotitan, and Carcharodontosaurus.

Researchers think Giganotosaurus may have kept a steady internal temperature like warm-blooded animals. This would have helped it grow fast and stay active. Its strong neck and powerful jaws let it bite quickly and hard to catch its food. The shape of its lower jaw, with a special "chin," may have helped it stay strong when biting down.

Discovery

In 1993, an amateur Argentine fossil hunter found the lower leg bone of a large meat-eating dinosaur while driving in the badlands near Villa El Chocón, in Neuquén province of Patagonia, Argentina. Experts came to dig up the bone. In 1994, paleontologists Rodolfo Coria and Leonardo Salgado announced their discovery.

In 1995, they named it Giganotosaurus carolinii, which means "giant southern lizard." They named it after the discoverer, Rubén Carolini. The skeleton is kept in the Ernesto Bachmann Paleontological Museum in Villa El Chocón. It has most of the vertebral column, the pectoral and pelvic girdles, the femora, and the left tibia and fibula. Almost 70% of the skeleton was found.

Description

Giganotosaurus was a very big meat-eating dinosaur that lived about 100 million years ago in what is now Argentina. Scientists think it might have been as large as a school bus, but because many bones are missing, it is hard to know its exact size. Some scientists think it was bigger than Tyrannosaurus, which is often called the biggest meat-eater, but others are not sure.

The skull of Giganotosaurus was long and had sharp teeth with tiny points, like a saw. Its bones had special shapes that helped scientists learn about how it looked. The body had strong bones in the neck and tail, and its legs were made for powerful movement.

Classification

Scientists first thought Giganotosaurus was related to a group of dinosaurs called Tetanurae. Later, they found it was part of a group called Allosauroidea, like Carcharodontosaurus and Acrocanthosaurus. These dinosaurs had special bones around their eyes.

As more of these dinosaurs were found, scientists learned more about them. Giganotosaurus was placed in a group called Carcharodontosauridae. It was one of the best-known members of this group.

Evolution

Scientists think very large theropods like Giganotosaurus grew huge because of conditions in their habitats. Giganotosaurus lived in South America, and its relatives lived in Africa and North America. This was during the Early Cretaceous period. Later, oceans separated the continents. Giganotosaurus lived on the southern continent of Gondwana, which included South America and Africa. They were likely the top predators there.

Paleobiology

In 1999, scientists studied the bones of Giganotosaurus and found they had similar patterns to those of Tyrannosaurus. This suggests both dinosaurs had a stable body temperature, like warm-blooded animals, which helped them grow quickly.

Locomotion

In 2001, researchers figured out how fast Giganotosaurus could run. They thought the top speed was about 14 meters per second (50 kilometers per hour or 31 miles per hour). Later studies suggested that Giganotosaurus, like other large theropods, might not have been able to run as fast as once thought, and may have moved more by walking.

Feeding

In 2002, scientists looked at the skull of Giganotosaurus and found it could move its head side to side easily. This, along with strong jaw muscles, allowed it to bite powerfully. Studies showed Giganotosaurus could deliver strong bites but not as strong as Tyrannosaurus. Its jaws were good for slicing through prey. Evidence suggests these dinosaurs might have hunted in groups, which would help when taking down large animals like sauropods.

Main article: oxygen isotope
Main article: thermoregulatory
Main article: metabolism
Main article: homeothermic
Main article: warm-bloodedness
Main article: cursorial
Main article: kinematic
Main article: ostrich
Main article: pursuit predator
Main article: bite force
Main article: torsional
Main article: newtons
Main article: bonebed
Main article: National Geographic

Paleoenvironment

Giganotosaurus was found in the Candeleros Formation. This area was formed a very long time ago, during the Early Cenomanian age of the Late Cretaceous period, about 99.6 to 97 million years ago. It was part of the Neuquén Group and the Río Limay Subgroup. The land had rivers, streams, and winds. There were also swamps, and soils that later turned into rock.

Giganotosaurus was probably the biggest hunter there. It lived with plant-eating dinosaurs like the titanosaurian sauropod Andesaurus, and other sauropods such as Limaysaurus and Nopcsaspondylus. Other hunters included the abelisaur Ekrixinatosaurus, the dromaeosaur Buitreraptor, and the alvarezsauroid Alnashetri. The area also had crocodiles like Araripesuchus, turtles, snakes, frogs, fish, and early mammals. Footprints show that birds and flying reptiles, called pterosaurs, were there too.