The strange way dinosaurs chewed

By | July 2, 2009

A novel analysis of microscopic scratches on fossilized teeth reveals how plant-eating duck-billed dinosaurs used a now-extinct type of jaw to chew their food. The study also suggests duckbills were more likely to graze on low-lying greenery than to chomp on tree leaves like giraffes (or like the dinosaurs in “Jurassic Park”).

The researchers behind the study, published online today in the Proceedings of the National Academy of Sciences, say the technique they used to uncover the tale of the teeth could be applied to other scientific mysteries as well.

“We did it by measuring literally hundreds and hundreds of scratches on these teeth, and then doing a statistical analysis of the directions of the scratches,” University of Leicester paleontologist Mark Purnell, who led the research, told me today.”The statistical analysis turned out to be quite a tricky business.”

The mouth of a hadrosaur has been compared to a “cranial Cuisinart,” with hundreds of teeth lined up in rows to chop up the tough plants of the late Cretaceous. But the dinosaurs didn’t have the complex jaw joint that mammals have, leaving scientists to puzzle over exactly how hadrosaurs did all that chewing.

Purnell and his colleagues say they found the answer after going through a three-dimensional analysis of the scratches left behind on fossilized hadrosaur teeth from Wyoming. Co-author Paul Barrett, a paleontologist at Britain’s Natural History Museum, said the dinosaurs chewed “in a completely different way [compared] to anything alive today.”

“Rather than a flexible lower-jaw joint, they had a hinge between the upper jaws and the rest of the skully,” Barrett explained in a news release describing the research. “As they bit down on their food, the upper jaws were forced outward, flexing along this hinge so that the tooth surfaces slid sideways across each other, grinding and shredding food in the process.”

via How dinosaurs chewed – Cosmic Log – msnbc.com.

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