World's smallest frog discovered in Papua New Guinea

The newly discovered frog, which fits in the center of a U.S. dime, is the world's smallest vertebrae.

STORY HIGHLIGHTS

• The new species is on average just 7.7 millimeters long
• Scientists have named the frog Paedophryne amauensis
• They skip the tadpole stage and are born frogs
• Previously smallest vertebrate was a fish

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, and calls out with a continuous series of high-pitched notes at dawn and dusk.

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.

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.

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.