A fossil discovered in Montana has given new momentum to the hypothesis that dinosaurs were thriving right up until a devastating meteor hit Earth 65 million years ago, causing their extinction. Scientists from Yale University have found what is believed to be the youngest dinosaur fossil ever found, thought to be from just before the mass extinction took place. The discovery, described in a study published in the online edition of the journal Biology Letters, contradicts the theory that the dinosaurs slowly went extinct before the cosmic impact. The fossil -- a 45-centimetre horn believed to be from a triceratops...