Vegetarian Dinosaurs Had Complex Teeth

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Vegetarian dinosaurs had complex teeth, according to ScienceNOW and ScienceDaily and e! Science News. Evidence from fossilised stomach contents and wear marks on their teeth indicates the large Hadrosaurs found throughout North America, Europe and Asia ate a great variety of tough plants, including grasses, ferns, horsetails and conifers. To grind up this tough fibrous diet these dinosaurs had large numbers of flat teeth, very different from the pointed teeth seen in most reptiles. A team of palaeontologists and engineers have carried out a microscopic study of the structure of teeth from a Hadrosaur named Edmontosaurus, from the collections of the American Museum of Natural History in New York City. Most reptiles have only two kinds of dental tissues, hard enamel and bone-like dentine, but Hadrosaur teeth had a complex structure involving six different kinds of dental tissue. Furthermore, the organisation of the tissues within teeth varied within and between the teeth, allowing different parts of the teeth to be used for either grinding or slicing plant material. Hadrosaurs have been nicknamed “cows of the Cretaceous” but their teeth were more complex than any living cows, horses, or other grazers. A typical mammal has four types of dental tissue: enamel, dentine1, cementum and dentine2. Gregory Sawyer, a professor of mechanical engineering at University of Florida commented: “Hadrosaurs’ teeth were incredibly complicated, among the most complex of any animal. These dinosaurs had developed a lot of tricks”. The researchers were impressed by the preservation of the teeth. Gregory Erickson, a biology professor at Florida State University commented: “We were stunned to find that the mechanical properties of the teeth were preserved after 70 million years of fossilization”. He went on to say "if you put these teeth back into a living dinosaur they would function perfectly."

Mark Purnell, a palaeobiologist at the University of Leicester in the United Kingdom suggested these teeth explain why Hadrosaurs survived until the very end of the age of the dinosaurs about 65 million years ago. According to Purnell, the ancestors of the duckbills did not have such sophisticated teeth and the evolution of the six-tissue structure may have allowed hadrosaurids to diversify and “explode” across the landscape. He commented: “They were able to broaden their niche and grind up food that other species struggled to process. In times of real resource shortages, they had something to fall back on”.

e! Science News, ScienceDaily

Editorial Comment: The researchers comment about the preservation of the teeth is a clue that the animal was buried rapidly. Check out sun and weather damage on any cow’s teeth when the cow dies and “hangs around” even a few seasons above ground.

These complex teeth may explain why Hadrosaurs survived, but survival does not explain the origin of either the teeth, or the dinosaur with them. Hadrosaur stomach contents show they obviously did well when there was plenty of fibrous vegetation to eat, but if they didn’t already have such complex grinding teeth they could not eat tough plants. But the presence of tough plants will never create genes for cementum, dentine and other tooth substances in dinosaurs that did not already have them. This study is a good example of the uselessness of evolution to explain the characteristics of living creatures. It is more logical to believe that Hadrosaurs were created as fully functional animals, complete with complex teeth ready to eat the abundant vegetation that grew in the original very good world that God created. (Ref. vegetarians, duck-billed dinosaurs, diet)

Evidence News 7 November 2012