Dinosaur Nostrils Move Ahead
Dinosaur artists have always placed the fleshy nostril relatively high and back from the tip of the snout. But in the 3 August issue of Science, a paleontologist argues for quite a different look: The sniffers ought to be farther forward and closer to the mouth.
Lawrence Witmer of Ohio University College of Osteopathic Medicine in Athens has been studying animal noses of all kinds for several years, as part of his DinoNose project. He's been intrigued by the sheer volume of many dinosaur noses. Triceratops, for example, devoted half the space in its skull to its nasal cavity, perhaps to cool its brain (Science, 5 November 1999, p. 1071).
Witmer first looked at the location of the fleshy nostril in birds and crocodiles--the closest living relatives of dinosaurs--as well as other animals. The challenge was to find the relationship between the position of the fleshy nostril, which is not preserved in dinosaurs, and the nasal opening in the bone. Time and again, the fleshly nostril was located toward the front of the bony nostril. If the pattern was true of the dinosaurs' closest living relatives, it was probably also the case for the dinosaurs themselves, Witmer says. And when Witmer checked dinosaur skulls of many kinds, he found traces of blood vessels similar to those near the front of the bony nostril in living animals.
His conclusion: Dinosaur nostrils were "pretty much like everybody else's, parked out in front." This makes sense, Witmer says, since fleshy nostrils positioned forward on the snout might improve the sense of smell. Fleshy nostrils near the mouth might enhance taste, too.
Other paleontologists say Witmer's evidence for moving the nostrils is strong and credit him with setting the record straight. "He's looking at something that a lot of us took for granted and applying some common sense to it," says paleontologist Christopher Brochu of the University of Iowa in Iowa City.