By Sean Henahan, Access Excellence
Philadelphia, Pa. (May 25, 1997)- Bigger, badder and older than
T-rex, but with a smaller brain, Giganotosaurus
is vying for the title of scariest dinosaur of all. Comparison of the giant
carnivores is also yielding important new paleogeographical and evolutionary
information from the Cretaceous Period.
T-rex's position as undisputed king of the carnivores was cast in doubt
with the announcement in 1995 of the discovery in Argentina of a
new dinosaur is called giganotosaurus carolinii. Giganotosaurus lived about
95 million years ago in the early part of the Late Cretaceous Period. The
monster lived 25 million years before T-Rex and, at nine tons, weighed
half again as much.
Comparison of T-Rex and Giganotosaurus
There are enough differences between Giganotosaurus and T. Rex to suggest
the two were not closely related. The teeth alone tell quite a story. The
teeth of Tyrannosaurus were longer and wider, but more variable
in size. While the tyrannosaur's teeth were suited for biting right through
flesh and bone, those of Giganotosaurus were
shorter, less variable and narrower, and are much better adapted for
"They are unusual teeth that are laterally compressed whereas those
of T. Rex are circular. They [Giganotosaurus's teeth] are for cutting."
Giganotosaurus's blade-shaped serrated teeth up to eight inches long indicate
it sliced through the flesh of its victims rather than crunching through
bones like T. Rex. says Dr. Jack Horner, Curator of Paleontology at the
Museum of the Rockies in Montana.
Horner was among the experts asked to render an opinion on the significance
of the Giganotosaurus find. "It is certainly the largest meat eating dinosaur
skull I have ever seen. I would agree that the skull has been reconstructed
accurately and is bigger than our T. Rex skull," he said.
The volume of new dinosaur discoveries in South America in recent years
has brought new information and debate about the world of the dinosaurs.
Newfound similarities between African and South American specimens has
stirred debate among geologists as well as paleontologists.
"Giganotosaurus ushers in a whole new era in our understanding of carnivorous
dinosaurs from the southern hemisphere," says Dr. Peter Dodson, a research
associate with the Academy and professor of veterinary anatomy and geology
at the University of Pennsylvania. "It is an extremely large and well preserved
animal. This is the first time we have had such complete knowledge."
Giganotosaurus was discovered by Argentinian scientist Dr. Rodolfo Coria,
Director of the Carmen Funes Museum in Plaza Huincul, Argentina.
"In recent years we have found one of the plant eating dinosaurs (rebbachisaurs)
from the same period as Giganotosaurus, which is very similar to one found
in Africa," says Coria. "We also have crocodiles from the same level and
locality which are similar to those in Africa. That is why we are proposing
that 100 million years ago Africa and South America were still connected
indicating the separation was more than 10 million years later than previously
thought. We have whole ecosystems which support this."
The body of new research implies that the continents stayed together
longer and the southern continents were a much greater mass than previously
believed. It also suggests the center of dinosaur evolution was located
the Southern Hemisphere. Many questions have also been raised about
North-South dinosaur migrations in the Americas.
Visitors to the Academy of Natural Sciences in Philadelphia will soon
be able to compare the monsters for themselves. Complete skeleton reconstructions
of both T-Rex and Giganotosaurus will be on display only at the Academy,
June 14 through September 14.
Related information on the Internet (Updated February 2007
AE: T-Rex with Gout
AE: Missing Dino-Bird Link
AE: T-rex No Vulture
AE Activity: Hands-on Dinosaur Science
AE: Jurassic Park Projects
AE: Jurassic Park Lesson Plan
Links to Natural History Museums