Hopping around the rainforests of Ecuador is a frog the size of a marble that can make itself look hopping mad. But remove it from the moisture and moss it’s used to, this spiky amphibian calms down, or at least its skin does. The new species is the first animal with a backbone that we know of that can change the texture of its skin.
Dubbed Pristimantis mutabilis, or “mutable rainfrog,” the tiny shape-shifter was described this week in the Zoological Journal of the Linnean Society. According to National Geographic, the frog was good enough at changing skin textures — from raised, tubular spikes to smooth, more frog-like skin — that the scientist who orginally scooped up a tiny specimen thought that she had brought back the wrong amphibian to the lab.
It took almost nine years since Juan Guayasamin, Tim Krynak and Katherine Krynak, and their team could gather up enough evidence to put forth Pristimantis mutabilis as a new species, but even with all that data they still aren’t sure how the frogs accomplish their shape-shift. “We speculate that explanatory variables involved in frog skin texture change are stress, humidity, and background,” the team writes. However, the mechanism behind the full-body punk-out is unclear.
Maybe the most famous example of the rapid skin texture change is the octopus, which uses structures in its skin composed of “muscular hydrostats” to squeeze and deform cells at will. More research will be needed to find out if these frogs have similar structures.
Although Pristimantis mutabilis is the first vetbrate to show this ability, the team did find another frog with a similar trick up its slimy sleeve. Called Pristimantis sobetes, this species inhabits the same areas that P. mutabilis does, and can also change its skin texture. However, genetic analysis revealed that the two shape-shifting species aren’t closely related, suggesting that shifting skin texture could be an independently evolved trait or a trait passed down from a common ancestor between the frogs.
That would mean there could be more species of punk rocker frogs hopping around our forests.
IMAGES: Juan M. Guayasamin et al.
STUDY: Guayasamin, J. M., Krynak, T., Krynak, K., Culebras, J. and Hutter, C. R. (2015), Phenotypic plasticity raises questions for taxonomically important traits: a remarkable new Andean rainfrog (Pristimantis) with the ability to change skin texture. Zoological Journal of the Linnean Society, 173: 913–928. doi: 10.1111/zoj.12222