The impact at Chicxulub in modern-day Mexico certainly contributed to the disappearance of the giant lizards and other creatures, but was by no means the sole cause, a team concluded in a study published in Nature Communications. Of 24 mollusk species which went extinct at one Atlantic island, 10 did so long before the extraterrestrial rock - either a comet or an asteroid - rammed into our planet some 66 million years ago, they wrote. The other 14 disappeared in a second extinction wave that started with the deadly strike contributing to the second-biggest ever mass extinction of life on Earth - including all non-avian dinosaurs. The species wipeout, said a trio of US-based researchers in the new paper, was caused by two periods of global warming - the first sparked by monster volcanic eruptions in what is India today, and the second by the space rock impact itself.

Study: 'One-two punch' delivered dino death blow. (2016, July 7). Manila Bulletin, p. B8.