Julián Faivovich, a herpetologist from the University of Buenos Aires, found the first ever fluorescent frog species. The South American polka dot tree frog, also known as Hypsiboas punctatus, has a body of muted greens, yellows and reds on its skin.
While they look like any other frog, these species give off a bright blue and green glow once lights are dimmed and the ultraviolet illumination switch is turned on. This glow, which shows the frog's ability to use fluorescent molecules, was unheard of in amphibians, although the way they use their fluorescence is different than that of other animals.
Scientific American noted that fluorescence requires light absorption, so it cannot happen in total darkness. Many ocean creatures, like corals, fish and even sharks can be fluorescent. But on land, only parrots and some scorpions have the ability to fluoresce. For these frogs, researchers thought that they will give off a red glow because of the pigment biliverdin. However, it appears that they were wrong: the red polka dots on the frog species turned out to be a red herring.
What came as a surprise, however, were the chemical compounds that caused the frog to glow. Chemist Norberto Peporine Lopes from the University of São Paulo and co-author of the study said that the fluorescence of the frogs are "amazing, and it's a new chemistry."
An article in the journal Nature said that there are three molecules responsible for the frogs' green fluorescence: hyloin-L1, hykoin-L2 and hyloin-G1. These molecules have a ring structure and a chain of hydrocarbons that are said to remain unique among the known fluorescent molecules in animals.
What is even more interesting is that these frogs emit a significant amount of light, contributing to about 18 percent to 29 percent of the total emerging light under twilight and nocturnal scenarios. Or, simply put, these frogs have about 18 percent as much light as a full Moon.
NPR noted that further studies are required to understand this particular frog species. Lopes also noted that there are other frogs that have similar body structures and even transparent skin, which could mean that frog fluorescence may be more common than originally thought.