Giga-noto-saurus means "giant southern reptile". Its fossil was unearthed in Argentina in 1994. 70 percent of the skeleton has been found. Near the Giganotosaurus, fossils were found of 75-foot-long plant eaters, presumably victims of this Giganotosaurus.

Size: Giganotosaurus was probably bigger than Tyrannosaurus rex , who was about 40-50 feet long, about 5 tons in weight and about 10 feet tall at the hips. Giganotosaurus, however, was more lightly built and had a much smaller brain case.

Fossils: Rodolfo Coria, a paleontologist from the Carmen Funes Museum in Neuquen, Argentina, excavated the Giganotosaurus from the Patagonia region of Argentina (in southern Argentina), which was originally (in 1994) found by a local auto mechanic whose hobby is hunting dinosaur bones. In honor of the discoverer, Ruben Carolini, the huge dinosaur has been named Giganotosaurus carolinii. It was named by Coria and Salgado in 1995.

	GIGANOTOSAURUS carolinii	TYRANNOSAURUS rex
Skull length	6 feet (1.8 m)	5 feet (1.5 m)
Hands	3 fingers	larger, with 2 fingers
Height at hips	12 feet (3.7 m)	10 feet (3 m)
Length	43 ft (13 m)	40 feet (12 m)
Weight	about 8 tons	about 5 tons
Teeth	long, knife-like, serrated - slicing action	conical, serrated - crushing action
Brain size, shape	small, banana shaped	larger and wider
When they lived	about 100-95 million years ago	about 65 million years ago
Where they lived	South America	North America
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In 1995 James Farlow of Indiana-Purdue University argued that a large T. rex could run no faster than 20 mph (32 kph), because if it did, a fall would probably be so severe as to kill it. T. rex weighed about 6 tons and was up to 20 feet (6 m) tall but Allosaurus was slightly smaller, about 3 tons and 16.5 feet (5 m) long. Farlow says that Rothschild's analysis is consistent with his theory since Allosaurus was smaller than T. rex (its smaller mass would make the impact much less powerful so the animal may have been able to recover after a running fall). Giganotosaurus and T. rex were quite similar in size, so Giganotosaurus may or may not have been a fast runner.

PRINTOUTS

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• Giganotosaurus fact sheet or the printable version