January 12th, 2012
12:45 PM ET

World's tiniest vertebrate is a frog

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

soundoff (25 Responses)
  1. Dawn M. Holcombe

    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

    January 19, 2012 at 6:01 pm |
  2. GOOD MORNING

    imagine the skeletal system of this frog on as big as a tadpole

    January 19, 2012 at 12:16 pm |
  3. LunaTek

    Too small to be the frog in my throat,
    This record of smallness he broke,
    If no metamorphosis,
    (perhaps minimorphosis?)
    I hope he won't dry out and croak!

    January 14, 2012 at 1:08 am |
  4. joeydds

    I have found frogs that small here is Arizona. They might want to look around a little more before saying worlds tiniest frogs lol
    https://www.facebook.com/photo.php?fbid=10100130161232819&set=a.10100130156063179.2468765.17832854&type=3&permPage=1 https://www.facebook.com/photo.php?fbid=10100130156143019&set=a.10100130156063179.2468765.17832854&type=3&permPage=1

    January 13, 2012 at 11:13 am |
  5. dee

    Our God, the Creator of all, is awesome!!!!!

    January 13, 2012 at 11:09 am |
    • Tim

      What a blessing that God has created an evolutionary process to allow such creatures to exist! Good job!!

      January 13, 2012 at 11:23 am |
  6. sonny chapman, Villie Platte,La.

    We may not be able to score against "Bama, but turn us loose on some frogs. Geaux Tigers

    January 13, 2012 at 10:59 am |
  7. TODAY

    I love frogs...this baby is soooo cute

    January 13, 2012 at 10:35 am |
  8. JOE

    Perhaps its the one Sarah Palin kissed!

    January 13, 2012 at 10:23 am |
    • Brian

      Joe, you're not a funny guy. Give it up and stop with your Palin obsession.

      January 13, 2012 at 10:46 am |
  9. viraaj

    I wanted to see but I think i squished it.. got another one?

    January 13, 2012 at 10:11 am |
  10. kam

    oh such a cute little froggie. I want to hold her

    January 13, 2012 at 10:08 am |
  11. Leucadia Bob

    [youtube=http://www.youtube.com/watch?v=9E3eY94Gu0k&w=640&h=390]

    January 12, 2012 at 7:59 pm |
  12. JollyGreenBud

    iT's sooo Hawt

    January 12, 2012 at 7:01 pm |
  13. Welcome to Reality

    "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

    January 12, 2012 at 6:58 pm |
    • pfeil1sp

      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.

      January 12, 2012 at 7:03 pm |
    • LuisWu

      Come back and post again... when you grow a brain.

      January 12, 2012 at 7:55 pm |
  14. Dr. Ruth

    It's not the size of your vertebrate, it's how you use it.

    January 12, 2012 at 6:24 pm |
  15. James K.

    That little fella is cute as a button!!!

    January 12, 2012 at 6:12 pm |
  16. Jules

    "All your resources is belongs to us."

    January 12, 2012 at 6:11 pm |
    • For Great Justice! All your base are belong 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.

      January 13, 2012 at 10:59 am |
      • Wut

        The cells would be the same size as any organism's cells. There will just be fewer of them.

        January 13, 2012 at 11:23 am |
  17. alateos

    That's pretty small...

    January 12, 2012 at 6:08 pm |
  18. Burbank

    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!

    January 12, 2012 at 6:07 pm |

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