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Published on May 1, 2012
Were dinosaurs already undergoing a long-term decline before an asteroid hit at the end of the Cretaceous about 65.5 million years ago? A new study led by scientists at the American Museum of Natural History gives a multifaceted answer.
The findings, published online on May 1, 2012, in the journal Nature Communications, suggest that in general, large-bodied, "bulk-feeding" herbivores were declining during the last 12 million years of the Cretaceous. But carnivorous dinosaurs and mid-sized herbivores were not.
"Few issues in the history of paleontology have fueled as much research and popular fascination as the extinction of non-avian dinosaurs," says lead author Steve Brusatte, a Columbia University graduate student affiliated with the Museum's Division of Paleontology. "Did sudden volcanic eruptions or an asteroid impact strike down dinosaurs during theirprime? We found that it was probably much more complex than that, and maybe not the sudden catastrophe that is often portrayed."
The research team, which includes Brusatte; Mark Norell, chair of the Museum's Division of Paleontology; and scientists Richard Butler of Ludwig Maximilian University of Munich and Albert Prieto-Márquez from the Bavarian State Collection for Palaeontology, both in Germany, is the first to look at dinosaur extinction based on "morphological disparity"—the variability of body structure within particular groups of dinosaurs.