MIAMI — The mass extinction that obliterated three-fourths of life on Earth due to the strike of massive asteroid millions of years ago, including non-avian dinosaurs, set the stage for the swift rise of frogs, said a study that shows how frogs became among the most diverse vertebrates in the world.
According to a study published this week in the Proceedings of the National Academy of Sciences, the slimy amphibians exploded in numbers and diversified in the millions of years after a massive asteroid wiped out the dinosaurs, taking advantage of the huge holes in the ecosystem that extinct creatures left behind.
An international team of researchers presented a new tree of life for frogs that helps solve longstanding riddles about relationships and sheds light on the history and pace of frog evolution.
As many as 10 types of frogs are believed to have survived the mass extinction some 66 million years ago, which erased three-quarters of life on Earth, said the report.
Unexpectedly, their analyses showed three major lineages of modern frogs — about 88 percent of living species — appeared simultaneously, evolving on the heels of the extinction event that marked the end of the Cretaceous Period and the beginning of the Paleogene.
Previous research suggested a more ancient origin of many of these modern frog groups.
“Frogs have been around for well over 200 million years, but this study shows it wasn’t until the extinction of the dinosaurs that we had this burst of frog diversity that resulted in the vast majority of frogs we see today,” said study co-author David Blackburn, associate curator of amphibians and reptiles at the Florida Museum of Natural History on the University of Florida campus.
“This finding was totally unexpected.”
Scientists, until now, believed that most modern frog species emerged at a steady pace between 66 million and 150 million years ago. But the latest research shows frogs burst onto the scene more like an “explosion,” as the tiny amphibians swept into habitats left vacant by other creatures.
The speed at which frogs diversified after the asteroid or comet impact that triggered a massive die-off of most plant and animal life suggests that the survivors were probably filling up new niches on Earth, Blackburn said.
“We think there were massive alterations of ecosystems at that time, including widespread destruction of forests,” he said.
“But frogs are pretty good at eking out a living in microhabitats, and as forests and tropical ecosystems rebounded, they quickly took advantage of those new ecological opportunities.”
Frogs rose to become one of the most diverse groups of vertebrates, with more than 6,700 described species. But sparse genetic data has hindered scientists from reliably tracing their evolutionary history and the links between frog families.Follow @gorkhapost