The demise of the dinosaurs led to an evolutionary explosion of modern mammals – or so we thought. It now seems that most mammalian lineages were around well before the dinosaurs died out, perhaps being held in check by other mammals.
From the fossil record alone, it looks as if the ancestors of most living mammals arose in a sudden burst of evolutionary divergence soon after the Cretaceous period ended 65 million years ago, filling ecological gaps left by the extinct dinosaurs.
To check this, Olaf Bininda-Emonds of the Technical University of Munich, Germany, and colleagues drew up an evolutionary “supertree”…
