The Largest Carnivorous Dinosaur May Not Have Been the T. Rex

They lived about 30 million years apart and never set foot on the same continent. Yet Giganotosaurus carolinii is always compared to the most popular dinosaur in the world, the beloved and famous Tyrannosaurus rexwho both compete for the position of the largest carnivorous dinosaur in history.

Everyone knows the T. Rex

Tyrannosaurus rex has reportedly been a media darling since 1906, when The New York Times called it "the prize fighter of the ancient world."

This apex predator, which had only been named a year earlier, had already become a subject of controversy at the American Museum of Natural History in Manhattan, where a preserved specimen Tyrannosaurus copy is preserved to this day. Many decades after its debut, T.rex was the largest known carnivorous dinosaur. In later generations, the theropod dinosaur was immortalized in the "Jurassic Park" franchise.

Nowadays we know an adult T.rex could be 12 feet (or 3.6 meters) high at the hip and 40 feet (12 meters) long. As such, the enormous size of Tyrannosaurus making it one of the largest carnivorous dinosaurs to ever walk the Earth.

But wait. A handful of other carnivorous dinosaurs matched or even surpassed the creature in size. Giganotosaurus belongs to this elite group - and it's part of a dinosaur mystery that has never been solved.

Giganotosaurus and Tyrannosaurus Rex: Prehistoric Beasts

T.rex And Giganotosaurus were both representatives of the theropod clade. (A "clade" is a group of organisms that includes a common ancestral species and all of its closely related descendants.) The theropod dinosaurs, with their hollow bones and bipedal legs, were (and are) a very successful group.

There was also a huge range of size within the clade, with the smallest raptors being about the size of modern dogs and the largest theropod dinosaurs growing to the size of a modest house. The list of documented theropods includes every carnivorous dinosaur discovered to date, quite a few herbivorous species, and every bird, living and extinct.

Tyrannosaurus rex and most other dinosaurs were wiped out at the end of the Cretaceous Period, a period of geologic time that lasted from 145 to 66 million years ago. Its conclusion marked the end of the Mesozoic Era in Earth's history, sometimes called the "Age of Dinosaurs."

Tyrannosaurus rexlong thought to be the largest carnivorous dinosaur, it lived in North America during the twilight of the Cretaceous Period and made its evolutionary debut about 68 million years ago. Our buddy Giganotosaurus was the product of a different time - and a different land area.

Giganotosaurus habitat

Native to western Argentina, it appeared in the Early Cretaceous Period, about 98 to 97 million years ago. South America was then a realm of giants. Huge sauropods, or "long-necked" herbivorous dinosaurs, roamed the landscape.

Some of these herbivores, such as Andesaurus And Limayasaurus - about 15 meters long, making them the largest dinosaur species in terms of body size. The local bestiary was supplemented with other animals such as crocodiles, early snakes and beaked herbivores.

Discovery of the largest carnivorous dinosaur yet

Doubtless Giganotosaurus kept his neighbors on their guard. The discovery of the holotype specimen was first announced in 1995 by paleontologists Rodolfo A. Coria and Leonardo Salgado.

In all the years since then we have still not found a complete skeleton. However, the fragmentary remains of backbone and tail vertebrae that we have do suggest Giganotosaurus was estimated to be at least 41 feet (12.5 meters) long. So Giganotosaurus could be a little longer than T.rex making it a contender for the title of largest carnivorous dinosaur.

On the other hand, a 2014 article published in the journal Plos Biology argued, T.rex had a much heavier build. Using the circumference of its femur bones, Roger Benson and his colleagues calculated that an adult Giganotosaurus had a body mass of about 13,448 pounds (6,100 kilograms). The same technique was used T.Rex weighing in at a staggering 16,975 pounds (7,700 kilograms).

Whatever species is really the largest carnivorous dinosaur, we know that they were truly giants for their time. These calculations are done using imperfect data, so we can't know Giganotosaurus' exact size until a nearly complete specimen of the large theropod is found.

Shark-like teeth helped the carnivorous dinosaur slice up prey

Weight differences are all well and good, but the jaws tell a better story. Anatomical evidence suggests that these two carnivorous dinosaurs used very different methods to kill their prey. Fat and banana-shaped, the sharp teeth of Tyrannosaurus would have been good at breaking bones.

Unlike, Giganotosaurus had long, thin teeth that looked a lot like recurved kitchen knives. Serrated on both sides, the pearly white teeth were set in a narrow snout and crocodile-like jaws. By the way, Giganotosaurus had a monstrous skull; scientists estimate the head was about 2 meters long.

Combine these features and you're looking at theropod dinosaurs that likely killed by slicing meat from their hapless prey-rather than crushing bones. Once bitten, a victim could bleed to death while the carnivore lurked nearby.

Great White Relatives

Giganotosaurus comes from one of the most intimidating families in the fossil record, the carcharodontosaurids. If you like sharks, that name should ring a bell: scientists call the great white Carcharodon carcharias. The word "carcharodontosaurid" roughly translates to "shark-toothed lizard" in Greek.

Steve Brusatte is a paleontologist at the University of Edinburgh who has studied these remarkable theropod dinosaurs. He was also a scientific advisor for one of the 'Jurassic World' films.

"The fossil record of carcharodontosaurids has expanded dramatically over the past decade, as people have found fossils all over the world, especially in South America and Africa, but also in Asia and Europe," Brusatte said in an email.

"Most carcharodontosaurids [like Giganotosaurus] were gigantic carnivorous dinosaurs with deep jaws and sharp, thin, almost shark-like teeth. They were the largest and most fearsome predators in many ecosystems during the early to mid-Cretaceous, before the rise of tyrannosaurs."

Indeed, T.rex had a few tiny ancestors. The first members of its lineage were human-sized predators that emerged in the late Jurassic period about 170 million years ago. The giant T.rex would not begin to evolve until the late Cretaceous, after the mighty carcharodontosaurids had become extinct.

"This change remains a mystery," Brusatte explains. "We don't really know why it happened, and it's one of the biggest remaining mysteries of dinosaur evolution, in my opinion."

Now that's interesting
You can't talk about theropod superlatives and ignore them Spinosaurus aegyptiacus. Our understanding of this spiny lizard is somewhat murky, but the picture is becoming clearer. In 2020, the scientific community discovered that this animal had a strange, paddle-shaped tail. Although its legs seem disproportionately short, experts theorize Spinosaurus had a total length of about 14 meters (47 ft), making it one of the largest theropod dinosaurs.

Original article: The largest carnivorous dinosaur may not have been the T. Rex