Shape-Shifting Frog Discovered

A picture illustrating how the frog, which was discovered in the Andes, can change texture. Zoological Journal of the Linnean Society

A new species of frog has been discovered that possesses a unique, shape-shifting ability never seen before in an amphibian.

Case Western Reserve University reports that the frog can change its skin texture in a matter of minutes, appearing to mimic the texture it is sitting on - a move designed to allow them to blend in with its surrounding to hide from predators, say researchers.

The frogs were discovered by wife and husband Katherine and Tim Krynak - the former a PhD student and the latter a projects manager from the university - when they were on a visit to a nature reserve called Reserva Las Gralarias in north-central Ecuador's Andean cloud forest.

Katherine Krynak describes how she scooped up the frog - which then had little spines earning it the nickname "punk rocker" - on a nightly search for wildlife in 2009, and kept it in a cup with a lid. When she opened the cup the next day, she thought she had picked up a different, smooth skinned frog.

She said: "I then put the frog back in the cup and added some moss. The spines came back... we simply couldn't believe our eyes, our frog changed skin texture! I put the frog back on the smooth white background. Its skin became smooth."

"The spines and coloration help them blend into mossy habitats, making it hard for us to see them," she added. "But whether the texture really helps them elude predators still needs to be tested."

The researchers have also found a relative of the frog, which has been named pristimantis mutabilis or 'mutable rainfrog', which is twice the size but has the same shape-shifting ability. This species, prismantis sobetes, was previously known but the shape-shifting was never before reported.

Katherine and Tim Krynak and colleagues from the Universidad Indoamérica and Tropical Herping in Ecuador published a manuscript this week in the Zoological Journal of the Linnean Society laying out their findings.

One implication from the findings is that the researchers are now facing a challenge to the established system of identifying species by their appearance, as species identified by just a few preserved specimens might have had changeable appearances.

The researchers are planning to continue their investigations into the mutable frogs in the reserve, and to see if they can discover a common ancestor to the related species.