In an apocalyptic, post-dinosaur world, frogs rose to be king

4 Jul 2017

Image: Arif Supriyadi/Shutterstock

In the thousands of years that followed the mass dinosaur extinction, frogs rose out of the ashes to thrive in a new world.

The humble frog might not draw much attention today but, around 66m years ago, the creature thrived in a world almost obliterated by a huge chunk of space debris.

The famous asteroid impact is best known for killing off dinosaurs, but the event caused much more havoc than that, with nearly three-quarters of all life on Earth wiped out in a single blow.

Future Human

From the ashes rose a creature that, at one point, had been just a small number of species, but in this post-dinosaur world, it thrived and branched off into thousands of different species.

This is according to new findings in a paper published in the Proceedings of the National Academy of Sciences by a team of researchers from the University of Florida.

The team had been trying to map a new family tree for frogs and discover how the creature evolved over millions of years, and its sudden surge in species surprised them.

Filling leftover niches

“Frogs have been around for well over 200m 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.

The rise in diversification, Blackburn suggested, was due to the frog stepping up to fill a few niches left by other creatures, many of whom had perished after the impact.

“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.”

Frog on a leaf

The Boophis marojezensis from Madagascar evolved after the dinosaur extinction. Image: Brian Freiermuth

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It wasn’t all good for the croaky creature, though. Despite the explosion in the number of tree frogs in the wake of the mass extinction, many other species were effectively snuffed out of existence.

“Except for a small handful of species, all other North American frogs are ‘post-dinosaur’ colonists,” Blackburn explained.

“If you could travel back to the time of T-rex in North America, there would be frogs, but the chorus you would hear at night would have been nothing like you’d hear today. They’re not even the same families.”

For Peng Zhang, corresponding author on the paper, the discovery highlights a major environmental worry today, as frog numbers are in decline due to humans destroying their habitat.

“Does that mean humans are making a huge extinction event even stronger than this one? We need to think about it,” he said.

Colm Gorey was a senior journalist with Silicon Republic