Researchers from the Centre National de la Recherche Scientifique (CNRS, France), the Museum National d´Histoire Naturelle (MNHN, Paris, France), the Université Pierre et Marie Curie (UPMC, Paris, France), the American Museum of Natural History (AMNH, New York, USA) and the European Synchrotron Radiation Facility (ESRF, Grenoble, France) have determined the diet and position in the food chain of ammonites.
Using synchrotron X-ray microtomography, the Franco-American team of scientists discovered exceptionally preserved mouth organs of ammonites, along with the remains of a meal that show that these ammonites dined on plankton. There was evidence of the consumption of snails in on specimen - three snails with one bitten in half.
There was sufficient detail to expose jaws, teeth, the radula (a kind of tongue covered with teeth), and multiple cusps on their radula teeth.. Tooth shape varies from saber to comb-like, and teeth are very slender.
Ammonites are extinct relatives of the squid and octopus that appeared about 400 million years ago (the Early Devonian) and experienced a population explosion in the early Jurassic and became extinct 65.5 million years ago, at the end of the Cretaceous.
The exposure of the ammonite diet explains their extinction. Plankton died off as a result of asteroid impact left the ammonite without a food source.
Isabelle Kruta of the Département Histoire de la Terre, Muséum National d'Histoire Naturelle in Paris, France,
Neil Landman, curator in the Division of Paleontology at the American Museum of Natural History, Paul Tafforeau of the European Synchrotron Radiation Facility, Fabrizio Cecca of the Laboratoire de Paléontologie, Université Pierre et Marie Curie in Paris, and Isabelle Rouget, Laboratoire de Paléontologie, Université Pierre et Marie Curie in Paris, are the authors of the paper.
The research was reported in two articles (see one and two) at the EurekaAlert site on January 6, 2010, and was published this week in Science.
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