The idea that dinosaurs were already in decline before an asteroid wiped most of them out 66 million years ago may be explained by a worsening fossil record from that time rather than a genuine dwindling of dinosaur species, suggests a new study led by University College London (UCL) researchers. The study, published in Current Biology, analyzed the fossil record of North America in the 18 million years up to the asteroid impact at the end of the Cretaceous period (between 66 and 84 million years ago). Taken at face value, these fossils—more than 8,000 of them—suggest the number of dinosaur species peaked about 75 million years ago and then declined in the nine million years leading up to the
