Une découverte intéressante pour mieux comprendre l'évolution des dents et des mâchoires:
Many have thought the first jawed vertebrates captured prey with toothless, scissor-like jaw-bones. However, new research published in Nature shows the earliest jawed vertebrates possessed teeth too, indicating that teeth evolved along with, or soon after, the evolution of jaws.
Palaeontologists from Curtin University, University of Bristol and the Natural History Museum collaborated with physicists from Switzerland to study the jaws of a primitive jawed fish called Compagopiscis.
The international team studied the Australian fossils of Compagopiscis using high energy X-rays at the Swiss Light Source at the Paul Scherrer Institut in Switzerland, revealing the structure and development of teeth and bones, without affecting the fossil.
Co-author Kate Trinajstic, of Curtin’s Department of Chemistry, said the research team was able to use new technology to visualise every tissue, cell and growth line within the bony jaws and study its development. The team then made comparisons to the embryology of living vertebrates, determining that placoderms, ancient armored fish that were the first fish to have jaws, also possessed teeth.
“It was a great achievement to finally solve the debate on the origins of teeth,” she said. “We’ve always known exceptionally preserved fossils, such as those from Western Australia, hold a lot of answers to many evolutionary questions, but research like this has been waiting for non-destructive technology to study fossils without touching them.”
The research team used a particle accelerator called a synchrotron as the X-ray source for performing non-destructive 3D microscopy of the sample.
It allowed the team to make a perfect computer model of the fossil that could be cut up in any way they wanted without damaging the fossil.
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