Coin-Size Frog Found -- One of World's Smallest

As the smallest known frog species in the world's second largest mountain range, this new amphibian is easy to miss.

But scientists searching the Andes mountains' upper Cosnipata Valley in southern Peru, near Cusco, spotted the coin-size creature--a member of the Noblella genus--in the leaf litter of a cloud forest between 9,925 and 10,466 feet (3,025 and 3,190 meters).

"The most distinctive character of the new species," scientists write in the February issue of the journal Copeia, "is its diminutive size." Females grow to 0.49 inch (12.4 millimeters) at most. Males make it to only 0.44 inch (11.1 millimeters).

What's most surprising is that the frog lives at such high elevations, said study co-author Alessandro Catenazzi, a postdoctoral researcher at the University of California, Berkeley. In general, larger animals are found at greater heights.