Dinosaurs' large noses may have been key to physiological...( National Science Foundation-funded re...)

With only bones for clues, scientists continue to puzzle over many details of dinosaur appearances and physiology. Detective work by a paleontologist at Ohio University now indicates that the creatures' fleshy nasal passages were larger than had been thought, which could lead to more-realistic depictions and greater understanding of their respiratory functions.

In the August 3 issue of the journal Science, National Science Foundation (NSF)-supported researcher Lawrence Witmer reveals that nostrils on many dinosaurs were much farther from the eyes and closer to the mouths than previously depicted. By comparing tell-tale markings on bones from their present-day relatives, he has shown that many dinosaurs had large nasal passages that might have been important for heat exchange and other key physiological processes.

Witmer is an associate professor of biomedical sciences and an anatomist in the university's College of Osteopathic Medicine. X-ray examinations of skulls from more than 65 surviving dinosaur relatives -- including crocodiles, birds and lizards -- helped him infer the probable location of cartilage, blood vessels and other soft tissues that made up the extinct creatures' nasal cavities.

He discovered that nearly all animals share these traits, which gives weight to his assertion that previous depictions of dinosaur nostrils were inaccurate.

"Our findings were consistent, even in turtles and mammals," Witmer said. "We saw an unusual commonality of how the nasal components relate and are positioned. It turns out that the nostril positioning applies to almost all animals."

As a result, scientists may have to change the conventional view of dinosaur nostrils, which have until now been based on the placement of cranial cavities near the eye sockets. Witmer found the largest nasal passages in horned dinosaur
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Contact: Tom Garritano
tgarrita@nsf.gov
703-292-8070
National Science Foundation
2-Aug-2001