First fluorescent frog found in Argentina

A group of scientists discovered the world’s first fluorescent frog (Hypsiboas punctatus) near Santa Fe in Argentina. The frog sports a muted palette of greens, yellows and reds under normal light, but emits a bright blue and green glow in the dark.

The scientists found that the South American polka dot tree frog uses fluorescent molecules totally unlike those found in other animals.

The findings were published on 13 March 2017 in Proceedings of the National Academy of Sciences.

Key highlights

• When the researchers trained an ultraviolet A flashlight on polka dot tree frogs, they were surprised to find that the animals gave off an intense greenish-blue glow instead of a faint red.

• The researchers expected to find red fluorescence in these frogs from a pigment called biliverdin.

• Three molecules namely, hyloin-L1, hyloin-L2 and hyloin-G1, found in lymph tissue, skin and glandular secretions of animals, are responsible for the green fluorescence.

• The molecules contain a ring structure and a chain of hydrocarbons. The closest similar molecules are found in plants.

Fluorescence in animals

• The ability to absorb light at short wavelengths and re-emit it at longer wavelengths is called fluorescence, a quality that is rare in terrestrial animals. Until now, fluorescence was unheard of in amphibians.

• It is still unclear why animals have the ability of fluorescence, although explanations include communication, camouflage and mate attraction.