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Hadrosaur chowdown -- grind, grind, grind
[June 30, 2009] WASHINGTON (AP) -- Think you grind your teeth? Pity the ancient hadrosaur. Their jaws weren't hinged in the same way as modern people and animals, and researchers have long wondered how these ancient animals handled food.
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A new study on scratch marks on hadrosaur teeth sheds some light on the subject, researchers report in Tuesday's edition of Proceedings of the National Academy of Sciences. "For millions of years, until their extinction at the end of the Cretaceous, duckbilled dinosaurs -- or hadrosaurs -- were the world's dominant herbivores. They must have been able to break down their food somehow, but without the complex jaw joint of mammals they would not have been able to chew in the same way," paleontologist Mark Purnell of the University of Leicester in England said in a statement. The pattern of scratches on the hadrosaur indicates that the movements of hadrosaur teeth were complex, involving up and down, sideways and front to back motion. Paul Barrett, a paleontologist at the Natural History Museum in London said the finding shows that hadrosaurs did chew, but in a completely different way from anything alive today. They had a hinge between the upper jaws and the rest of the skull so that "when they bit down on their food the upper jaws were forced outwards, flexing along this hinge so that the tooth surfaces slid sideways across each other, grinding and shredding food in the process," he said in a statement. ___ On the Net: PNAS: http://www.pnas.org/ |
