ATHENS, Ga., March 28 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, saysthe mammals we know today "are actually quite old and just flew under the radar of everything that was out there." Copyright 2007 by UPI
