Tiny Toad to Tell Secrets?
September 28, 2013—The tiny pebble toad, which is unique for its climbing ability, may tell secrets through its DNA about the age of giant South American tepuis (mesas) on which it lives. National Geographic grantee and herpetologist Bruce Means explains their uniqueness while on an expedition to find the little creatures in Guyana.
Transcript
DR. BRUCE MEANS, HERPETOLOGIST & NATIONAL GEOGRAPHIC GRANTEE
And there on a little leaf about that big sat one these priceless little babies.
This is fabulous! I do want to stay another night. I like to do some more work on their ecology. I didn't have my camera with me and yadda, yadda, yadda...and on, and on, and on...and yadda, yadda, yadda. But we're successful! [Cheering in background] Yahoo!
This is a representative of a group of toads called the pebble toads, toads or frogs. But this one is a special toad amongst toads because it is a climber. It's arboreal.
This particular one is one I'm especially interested in because pebble toads commonly occur on the summits of the highest tepuis. Tepuis may be among the most ancient evolutionary islands because they're high in altitude. They're separated from each other. And the animal and plants on the summit of tepuis are unique there because of the unique climates on summits. It is a biodiversity hotspot on the planet.
This is potentially the ancestor because it is in the lower cloud forests that occur at the base of the cliff of the taller tepuis. This one may be the ancestor to all those on the summit. We're going to look at those—the DNA from those on the summits—to see whether this is in fact is...oh...the ancestor...I'll get her in a minute.
Tepuis are an evolutionary archipelago just like the Galapagos Islands. But what's really interesting about tepuis is they are potentially much older.
This is a small crevice in rock leading down to this giant chasm I want to explore-the forest at the bottom of it.
I got down in the bottom. Spent three days and three nights and found the animal. It took at least 36-hours to recognize how to find it.
We assume the toads are as ancient as the tepuis. But guess what? This work is beginning to show something very interesting. Not only the pebble toads, but many of the reptiles and amphibians that have gotten to the summits are actually pretty recently arrived. And this is a big paradigm shift. A paradigm shift means everybody thought one thing and the whole world has to change now to think another thing. And that's what some of the data I'm gathering is all about: is trying to corroborate this latest finding.
And then we have to understand how they get there. Did they climb up the cliff? Did a storm suck them up from somewhere else and drop them on the top? So, as in all science, when you investigate something you always come up with a lot more questions than you get answers.