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NSF Press Release


Embargoed until 2:00 P.M. EDT

NSF PR 01-60 - August 2, 2001

Media contacts:

 Tom Garritano, NSF

 (703) 292-8070


 Kelli Whitlock,
 Ohio University

 (740) 593-2868

Program contacts:

 Jack Hayes, NSF

 (703) 292-7887


 Lawrence Witmer,
 Ohio University

 (740) 593-9489

This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date; please see current contact information at media contacts.

Dinosaurs' Large Noses May Have Been Key to Physiological Processes
National Science Foundation-funded research redefines the extinct creatures' appearance

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 telltale 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 dinosaurs like Triceratops, duck-billed dinosaurs, and brontosaurs like Diplodocus, the latter of which was 80 to 90 feet long and weighed more than 40 tons.

Other scientists had studied dinosaur noses, Witmer said, but their focus was primarily on olfactory functions. He isn't only interested in how the animals were able to smell; his main goal is understanding overall dinosaur physiology. As his research progressed, Witmer was surprised to learn that no one had previously examined the position of nostrils.

"Learning the biological rules for assembling the bones of extinct animals, like dinosaurs, is notoriously hard," said Jack Hayes, NSF program director for ecological and evolutionary physiology. "But learning the rules for how to place the rest of the animal on those bones may be even harder. Because both the general public and many biologists are keenly interested in dinosaurs, new tools for reconstructing the anatomy and biology of dinosaurs are valuable. What's exciting about Witmer's findings is that they may make it possible to explore the function of dinosaur respiratory systems in more detail."

photo of new position of the nostrils on the sauropod dinosaur diplodocus; caption is below

This rendering reflects the new position of the nostrils on the sauropod dinosaur Diplodocus (left and bottom right). Top right is the skull of Diplodocus; middle right is the traditional view with the nostril located more to the rear of the head, which has been refuted by the new research by Ohio University's Lawrence Witmer.

A larger version is here.

Copyright Science/Paintings by M. W. Skrepnick under the direction of L. M. Witmer

photo of Ohio University paleontologist; caption is below
Ohio University paleontologist Lawrence Witmer.

Photo by: Jo McCulty.

changing nostril position in Tyrannosaurus rex; caption is below

Changing nostril position in Tyrannosaurus rex. The middle image is the traditional view with the nostril located more to the rear of the head. The image at lower right is a new restoration based on Witmer's study reflecting the forward position of the nostril. The image at upper left is the skull.

A larger version is here.

Copyright Science/Paintings by W. L. Parsons under the direction of L. M. Witmer

Note to Editors

See also:
Statement by Dr. Jack Hayes, Program Director for Ecological and Evolutionary Physiology, on dinosaur nasal discovery


Note to news media: All images are EMBARGOED UNTIL 2 P.M. EST AUG. 2, 2001.
To receive these images at 300 dpi via e-mail, contact Kelli Whitlock at (740) 593-2868 or To receive a copy of the journal article on which this is based, contact Science at (202) 326-6440 or

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