Researchers in Germany have discovered that the Namib Web-Footed Gecko – a species of lizard endemic to the Namib Desert and therefore found in arid areas of Angola, Namibia and South Africa – fluoresces bright neon green stripes down their sides and around their eyes under UV light.
Fluorescence is where light is absorbed and then emitted at a longer wavelength. Fluorescence in this species is so bright that they are considered among the brightest fluorescing vertebrates. What’s more, this species appears to have developed an entirely unique method of fluorescence using guanine crystals located in pigment cells or iridophores – something not before observed in four-limbed animals.
Despite fluorescence being increasingly reported in a wide range of animals, it’s rare that a biological function can be attributed to this feature. The Namib Web-Footed Gecko may have a glimmer of an answer to the reason for its own fluorescence given the following clues: the places that light up on its body are extremely visible due to the brightness of the fluorescence, geckos are renowned for their colour vision even at night, the Namib Desert experiences extremely bright moonlight with no obstructions, the areas of the body that fluoresce are not visible from above but instead from an angle where other geckos may be likely to observe, and these geckos are social if they encounter another of their kind, even licking dew off one another. It would therefore appear that geckos may use this fluorescence socially in some way, though this has yet to be shown.
The Namib Web-Footed Gecko is rarely found in South Africa – it is restricted to the arid region just south of the Namib Desert. Until recently it was suspected to have gone locally extinct in that region possibly from a culmination of threats raised by agricultural development, housing development, and mining practices, but has since been reported in two sightings on the Virtual Museum. In South Africa this species is therefore listed as Critically Endangered, though the conservation status in Namibia, its stronghold, has yet to be evaluated. The gecko is also desirable in the pet trade.
Read more in the original article or a summary written by one of the authors on their website below:
Original article: https://www.nature.com/articles/s41598-020-79706-z
Author’s summary: http://www.markscherz.com/archives/4715
Text: Dr Cora Stobie.
Video credit: Video published in the original paper showing the Namib Web-Footed Gecko under UV illumination and visible light. Video: David Prötzel. Reproduced under Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/) from the publication https://doi.org/10.1038/s41598-020-79706-z.