ATHENS, Ohio (Dec. 8, 2008) Paleontologists have long known that dinosaurs had tiny brains, but they had no idea the beasts were such airheads.
A new study by Ohio University researchers Lawrence Witmer and Ryan Ridgely found that dinosaurs had more air cavities in their heads than expected. By using CT scans, the scientists were able to develop 3-D images of the dinosaur skulls that show a clearer picture of the physiology of the airways.
"I've been looking at sinuses for a long time, and indeed people would kid me about studying nothinglooking at the empty spaces in the skull. But what's emerged is that these air spaces have certain properties and functions," said Witmer, Chang Professor of Paleontology in Ohio University's College of Osteopathic Medicine.
Witmer and Ridgely examined skulls from two predators, Tyrannosaurus rex and Majungasaurus, and two ankylosaurian dinosaurs, Panoplosaurus and Euoplocephalus, both plant eaters with armored bodies and short snouts. For comparison, the scientists also studied scans of crocodiles and ostriches, which are modern day relatives of dinosaurs, as well as humans.
The analysis of the predatory dinosaurs revealed large olfactory areas, an arching airway that went from the nostrils to the throat, and many sinusesthe same cavities that give us sinus headaches. Overall, the amount of air space was much greater than the brain cavity.
The CT scans also allowed Witmer and Ridgely to calculate the volume of the bone, air space, muscle and other soft tissues to make an accurate estimate of how much these heads weighed when the animals were alive. A fully fleshed-out T. rex head, for example, weighed more than 1,100 pounds.
"That's more than the combined weight of the whole starting lineup of the Cleveland Cavaliers," Witmer said.
Witmer suggests that the air spaces helped lighten the load of the head, making it about 18 percent lighter than it would have bee
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