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When Dinosaurs Shrug

By voltagegate on March 29, 2007.

The tale of our furry ancestors will have to be retold:

U.S. and European researchers are challenging the idea that the mass extinction of dinosaurs played a major role in the evolution of mammals.

The report, published in the journal Nature, contains a new evolutionary tree for mammals that puts the major diversification of today's mammals long after a die-off of the dinosaurs some 65 million years ago.

"We have found that when you fuse all of the molecular trees with the fossil evidence, the timing does not work," University of Georgia Institute of Ecology Director John Gittleman said in a release. "The preponderance of mammals really didn't take off until 10 (million) to 15 million years after the demise of the dinosaurs." Scientists combined more than 2,500 partial "trees" constructed using molecular data and the fossil record to create the first virtually complete mammalian tree. Lead author Olaf Bininda-Emonds of the University of Jena, Germany, says

the mammals we know today "are actually quite old and just flew under the radar of everything that was out there."

I hope the National Museum of Natural History has the resources to make some adjustments to their new mammal exhibit (which is beautiful, by the way, complete with storm effects in certain areas).

Tags
evolution

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I don't think they need to adjust the exhibit! The fossil record still shows an impressive diversification after the KT event, at least in some areas. This molecular study is VERY cool, but it is not a test of the post KT boundary hypothesis.

See:

http://gregladen.com/wordpress/?p=594

I heard an interview with the author on NPR. His conclusion seemed to be that the mammals that existed at the point of the dinosaurs' extinction were too small to be direct competitors who could replace the dinosaurs in their niches. So it supposedly took several million years of diversification before that occurred. I agree with Greg that this study is being oversold a bit.