The world's smallest vertebrate - animals that have a backbone - is a frog that could sit within the confines of your fingernail, a new study reports.
Scientists found the new species, which on average is just 7.7 millimeters long, in the southwestern Pacific island nation of Papua New Guinea.
The frog, scientifically named Paedophryne amauensis, spends its life in moist leaf litter on the floors of tropical wet-forests. Males call out with a continuous series of high-pitched notes at dawn and dusk, resembling the sound of crickets, says Christopher Austin, associate professor at Louisiana State University who led the team that discovered the frog.
"We think the really small body size is an evolutionary adaptation to occupy this really moist, leaf litter niche in New Guinea," Austin said. Typically, small frogs dry out quickly, but this tiniest species has a habitat that stays moist for most of the year.
Describing their findings in the online research journal PLoS ONE, researchers say the animals have simplified skeletons and are born directly as frogs, as opposed to first going through a tadpole stage. Researchers believe these creatures eat even smaller animals, such as mites, Austin said.
The discovery "is of considerable interest to biologists because little is understood about the functional constraints that come with extreme body size, whether large or small," the report in the journal states.
Previously the smallest vertebrate was believed to have been a fish known as Paedocypris progenetica, which matures at 7.9 millimeters. There has been speculation that aquatic habitats are home to the world's smallest and largest vertebrates, but this frog contradicts that theory, Austin says.
Although the smallest frogs are just being reported on now, they are locally abundant, Austin said.
The discovery reveals that tiny frogs "are not merely curiosities, but represent a previously unrecognized ecological guild. Such discoveries are increasingly critical in this time of global amphibian declines and extinctions," the report says.
CNN's Elizabeth Landau contributed to this report
I'm pretty sure I played with tree toads that small in Iowa as a kid! And yes all the cells and orans would be the same as ours, but it's respiratory, cardiac, digestive system would have to be different because of the size constraints. bl4ck0utsUn
imagine the skeletal system of this frog on as big as a tadpole
Too small to be the frog in my throat,
This record of smallness he broke,
If no metamorphosis,
I hope he won't dry out and croak!
I have found frogs that small here is Arizona. They might want to look around a little more before saying worlds tiniest frogs lol
Our God, the Creator of all, is awesome!!!!!
What a blessing that God has created an evolutionary process to allow such creatures to exist! Good job!!
We may not be able to score against "Bama, but turn us loose on some frogs. Geaux Tigers
I love frogs...this baby is soooo cute
Perhaps its the one Sarah Palin kissed!
Joe, you're not a funny guy. Give it up and stop with your Palin obsession.
I wanted to see but I think i squished it.. got another one?
oh such a cute little froggie. I want to hold her
iT's sooo Hawt
"We think the really small body size is an evolutionary adaptation..." Of course they were going to say it's a result of evolution. What else would they say? "This frog appears to be a sin against nature. It clearly flys against everything we know about evolution." etc etc etc
Good job truncating the sentence buddy. "We think the really small body size is an evolutionary adaptation to occupy this really moist, leaf litter niche in New Guinea." Meaning changes when you consider the rest of the context.
Come back and post again... when you grow a brain.
It's not the size of your vertebrate, it's how you use it.
That little fella is cute as a button!!!
"All your resources is belongs to us."
Somebody set up us the Frog!
Seriously, though... awesome picture and cool article...
One of the neatest creatures I've ever seen. Can you imagine the size of the organs and cells of this frog? Microscopic resource transfers of blood through microscopic capillaries... wow.
To think deeper, what does it see with its eyes? How good is its hearing? How big are its ear components? How big is the olfactory? The questions just beg more questions that make me curiouser and curiouser!
Peace. Vivid Peace.
The cells would be the same size as any organism's cells. There will just be fewer of them.
That's pretty small...
So cute I almost passed out! The little Sierran Tree Frogs where I live are the size of that dime when they first emerge. They would dwarf that little guy!