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10 Facts About Giganotosaurus

What You Need to Know About the Giant Southern Lizard



Giganotosaurus' long, narrow skull housed a long, narrow, banana-shaped brain (Wikimedia Commons)


At 10 tons fully grown, Giganotosaurus was the second-largest theropod that ever lived (Dmitri Bogdanov)


Like T. Rex, Giganotosaurus had relatively stunted front arms, which likely still served an important function (Sergey Krasovskiy)

An up-and-comer in the dinosaur bestiary, Giganotosaurus has lately been attracting as much press as Tyrannosaurus Rex did in its heyday. Here are 10 facts you may (or may not) have known about this terrifying meat-eater. (See also a gallery of Giganotosaurus pictures.)

1. The name Giganotosaurus has nothing to do with "gigantic."

Giganotosaurus (pronounced GEE-gah-no-toe-SORE-us) is Greek for "giant southern lizard," not "gigantic lizard," as it's often mistranslated (and mispronounced). This common error can partly be traced to prehistoric animals that do, in fact, partake of the "giganto" root--the most notable being the giant oviraptor Gigantoraptor and the giant prehistoric snake Gigantophis.

2. Giganotosaurus may have preyed on Argentinosaurus.

Direct proof is lacking, but the discovery of Argentinosaurus bones in the proximity of those of Giganotosaurus hints at a predator-prey relationship. Since it's hard to imagine a lone Giganotosaurus taking down a 50-ton Argentinosaurus adult, this may be a hint that Giganotosaurus hunted in packs. (For an analysis of this encounter, see Giganotosaurus vs. Argentinosaurus - Who Wins?)

3. The closest relatives of Giganotosaurus were Carcharodontosaurus and Tyrannotitan.

There's something about giant predatory dinosaurs that inspires paleontologists to come up with cool-sounding names. Carcharodontosaurus ("great white shark lizard") and Tyrannotitan ("giant tyrant") were both close cousins of Giganotosaurus, though the first lived in northern Africa rather than South America. (The exception to this rule was the plain-vanilla-sounding Mapusaurus, another Giganotosaurus relative.)

4. Giganotosaurus was discovered by an amateur fossil hunter.

Not all dinosaur discoveries are made by trained professionals. Giganotosaurus was unearthed in the Patagonian region of Argentina, in 1993, by an amateur fossil hunter named Ruben Dario Carolini. The paleontologists who examined the "type specimen" acknowledged Carolini's contribution by naming the new dinosaur Giganotosaurus carolinii.

5. Giganotosaurus was bigger than T. Rex...

Part of what has made Giganotosaurus so popular, so quickly, is the fact that it slightly outweighed Tyrannosaurus Rex: full-grown adults may have tilted the scales at about 10 tons, compared to a little over nine tons for T. Rex. Even still, Giganotosaurus wasn't the biggest meat-eating dinosaur; that honor, pending further fossil discoveries, belongs to the northern African Spinosaurus.

6. ...and it was probably faster than T. Rex, too.

There has been a lot of debate lately about how fast T. Rex could run; some experts insist this supposedly fearsome dinosaur could only attain a top speed of a relatively pokey 10 miles per hour. Based on an analysis of its skeletal structure, it seems that Giganotosaurus was a bit fleeter, perhaps capable of sprints of 20mph or more (at least for short periods of time).

7. Giganotosaurus had an unusually small brain for its size.

It may have been bigger and faster than Tyrannosaurus Rex, but oddly enough, Giganotosaurus seems to have been a relative dimwit, with a brain only about half the size of its more famous cousin. Adding insult to injury, to judge by its long, narrow skulll, Giganotosaurus' tiny brain appears to have been the approximate shape and weight of a banana.

8. Giganotosaurus is the largest theropod to be discovered in South America.

Although it wasn't the largest theropod of the Mesozoic Era, Giganotosaurus takes the crown as the largest meat-eating dinosaur of Cretaceous South America. (Fittingly enough, its presumed prey Argentinosaurus holds the title of "largest South American sauropod.")  South America, by the way, is where the very first theropod dinosaurs evolved, way back toward the middle Triassic period.

9. To date, no one has found a complete Giganotosaurus skeleton.

As is the case with many dinosaurs, Giganotosaurus was  "diagnosed" based on incomplete fossil remains, in this case of a single adult specimen. The skeleton discovered by Ruben Carolini in 1993 is about 70 percent complete, including the skull, hips, and most of the back and leg bones. To date, mere fragments of the skull of a second individual have been found.

10. Giganotosaurus preceded T. Rex by 30 million years.

With all those comparisons based on size, speed, and intelligence, you might imagine that Giganotosaurus was a contemporary of Tyrannosaurus Rex. In fact, this gigantic dinosaur prowled the plains and woodlands of South America about 95 million years ago, a whopping 30 million years before its more famous relative appeared in North America.

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