Comparison between the three herbivores, however, is difficult because scientists have only found few vertebrae of Puertasaurus, and while the skeleton of Futalognkosaurus is fairly complete, scientists have not uncovered any bones from its limbs.
North America's dinosaurs don't even compare in size, Mackovicky added in a phone interview. "Dinosaurs do get big here, but nothing near the proportions we see in South America."
The site where Futalognkosaurus was found has been a bonanza for paleontologists, yielding more than 1,000 specimens, including 240 fossil plants, 300 teeth, and the remains of several other dinosaurs.
"As far as I know, there is no other place in the world where there is such a large and diverse quantity of fossils in such small area. That is truly unique," said Alexander Kellner, a researcher with the Brazilian National Museum and co-author of the dinosaur's scientific description.
Copyright 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
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