Scientists discover shape-shifting frog in Ecuador cloud forest

Mutable rainfrog changes texture from smooth to shiny

By DTE Staff
Published: Tuesday 24 March 2015


A frog in Ecuador’s Andean cloud forests can rapidly change skin texture in minutes, appearing to mimic the texture it sits on.

Katherine Krynak, a PhD student at the US’ Case Western Reserve University and her husband Tim Krynak, project manager at Cleveland Metroparks Natural Resources Division, discovered the new species, called the mutable rainfrog (Pristimantis mutabilis), in 2006 at nature preserve Reserva Las Gralarias. They nicknamed the amphibian the “punk rocker” frog for its thorn-like spines. It wasn’t until three years later that the couple discovered the species’ secret shape-shifting skills, which may help the marble-size frog be better camouflaged in its mossy surroundings.

The couple, and colleagues from Universidad Indoamérica, Ecuador and Tropical Herping, an organisation committed to discovering, and studying reptiles and amphibians, co-authored a paper describing the new animal and skin texture plasticity in the Zoological Journal of the Linnean Society this week.

Juan M Guayasamin of Universidad Tecnológica Indoamérica, Ecuador, and the lead author of the paper performed morphological and genetic analyses showing that  mutabilis was a unique and undescribed species. Carl R. Hutter, from the University of Kansas, studied the frog's calls, finding three songs the species uses, which differentiate them from relatives. The fifth author of the paper, Jamie Culebras, assisted with fieldwork and was able to locate a second population of the species. Culebras is a member of Tropical Herping.

Guayasamin and Hutter discovered that Prismantis sobetes, a relative with similar markings but about twice the size of P mutabilis, has the same trait when they placed a spiny specimen on a sheet and watched its skin turn smooth. P Sobetes is the only relative that has been tested so far.

Because the appearance of animals has long been one of the keys to identifying them as a certain species, the researchers believe their find challenges the system, particularly for species identified by one or just a few preserved specimens. With those, there was and is no way to know if the appearance is changeable.
The Krynaks plan to return to continue surveying for mutable rain frogs and to work with fellow researchers to further document their behaviours, lifecycle and texture shifting, and estimate their population, to improve scientific knowledge and ability to conserve the paradigm shifting species.

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