Camouflage is essential for a number of species to escape potential attack from their predators; it allows them to blend in their environment without being noticed so that they do not fall prey to other organisms in their ecosystems. New to the list, a species of frog named Pristimantis mutabilis with the ability to change its skin texture to mimic the surface it is on has been documented in a paper published in the Zoological Journal of the Linnean Society.
The shape-shifting Pristimantis mutabilis. Photo credits: Tim Krynak.
The discovery of the frog’s ability marks the first time that amphibians have been found to change their skin texture. However, the scientists later realised that the skin-morphing trait of the frog is also displayed by a close relative that has been known to science for a while now.
Researchers Katherine and Tim Krynak came across the Pristimantis mutabilis during an exploration of a nature reserve in Ecuador’s western Andean cloud forest some years ago. The unfamiliar spiny frog was spotted on a mossy leaf. The team immediately noticed that it belonged to an unknown species. They therefore got hold of the creature and brought it with them for a photoshoot. They nicknamed it “punk rocker”.
The Andean cloud forest in Equador where the Krynaks discovered the mysterious tiny frog. Photo credits: Tim Krynak.
The shape-shifting frog when discovered back in 2006 when Tim and Katherine Krynak spotted it for the first time. Photo credits: Tim Krynak.
The two researchers soon found that the tiny frog displayed a peculiar ability: when placed on a smooth sheet for a photoshoot, its skin texture was modified to a smooth surface. It was then put into a cup filled with moss to ensure that it was the same creature that was discovered in the nature reserve earlier. To the surprise of the Katherine and Tim Krynak, the frog quickly changed to its previous spiky appearance.
“The spines came back… We simply couldn’t believe our eyes, our frog changed skin texture,” Katherine Krynak said in a statement. “I put the frog back on the smooth white background. Its skin became smooth.”
The spines and coloration of the frog were observed to assisting it to blend into mossy backgrounds. However, it was not confirmed yet whether the change in texture actually helps it to flee from predators. Therefore, researchers from the Universidad Tecnológica Indoamérica, colleagues of the discoverers, decided to fully document the small frog.
Further investigation showed that the frog can change its texture in about 3 minutes. Morphological and genetic analysis thereafter confirmed that it was indeed a new species previously unknown to science. The scientists then coined the scientific name Pristimantis mutabilis, which is now also commonly known as the mutable rainfrog.
Skin-texture variation over the course of 330 seconds. The picture above depicts the skin texture variation in one of the Pristimantis mutabilis from Reserva Las Gralarias. The skin texture is shown to change from highly tubercular to almost smooth. Photo credits: Zoological Journal of the Linnean Society/ Tim Krynak.
The known close relative of the frog mentioned before, the P. sobetes, was then brought to the attention of the researchers. They found that the latter had remained unnoticed (prior to the discovery of the P. mutabilis) as to its skin-morphing ability.
Adult male (left) and adult female of Pristimantis sobetes. Photo credits: Tropical Herping.
The findings suggest that yet other Pristimantis frogs might be displaying this feature. Moreover, this implies that one species might have been described as two different ones in the past because of the lack of knowledge relating to the skin-morphing. This now constitutes further ground for researchers to dig into.