Newly Discovered Gecko Gets Extremely Nude in Order to Survive

The lizard’s ability to trash its outer scales could yield insights into regenerative medicine.

Feb 8 2017, 2:00pm

Geckolepis megalepis. Image: F. Glaw

You know that trope in horror movies, where the villain grabs someone by their clothes only to be foiled when the victim wriggles free, leaving the abandoned garments in the hands of the thwarted killer?

It turns out that Geckolepis megalepis, a newly identified species of gecko described in the journal PeerJ on Tuesday, relies on exactly the same strategy—except this critter gets scared out of its actual skin.

As part of the larger "fish-scale" gecko genus, the nocturnal lizard has evolved special tearable skin that can be discarded in an instant, allowing the nude animal to slither away from would-be predators. Its scales grow back in a matter of weeks, so the geckos can live to strip another day.

Images show G. megalepis in various states of undress. Image: Scherz MD, Daza JD, Köhler J, Vences M, Glaw F. (2017)

Gross? Yes. Effective? Immensely. In fact, according to the paper's authors, this skin-shedding superpower makes the Madagascan lizard "taxonomically challenging" to research because it ends up flashing field scientists whenever they venture too close. Geckolepis megalepis is especially difficult to study due to its scale size, which is unprecedented in geckos and correlates to speedier removal.

"The new species has the largest known body scales of any gecko (both relatively and absolutely), which come off with exceptional ease," according to the paper, entitled "Off the Scale," which was led by Mark Scherz, a PhD student in herpetology at the Zoologische Staatssammlung, München in Germany.

"Indeed, the process of collection often damages even the most intact specimens [...] These factors, combined with the secretive nature and cryptic colouration of this genus, have largely hindered progress on resolving its species taxonomy."

Scientists have tried a few different methods to get around this tearaway tissue issue, including capturing the geckos in plastic bags or cotton-wool traps. Even then, some scales are likely to instinctually lost, which obfuscates the processes of correctly categorizing the animals into a broader family tree.

READ MORE: Watch this Gecko-Inspired Space Junk Collector Practice Its Moves

To get around this problem, Scherz and his colleagues studied the skeletons and internal structure of euthanized gecko specimens with micro-computed tomography (micro-CT) scans. This method led to the identification of the new animal, which is the first fish-scale gecko to be recognized as a unique species in 75 years.

The team also found that Geckolepis maculata, a related species discovered 150 years ago, has a different line of descent than has been previously assumed. "This is just typical of Geckolepis," Scherz said in a statement. "You think you have them sorted out, but then you get a result that turns your hypothesis on its head. We still have no idea what Geckolepis maculata really is—we are just getting more and more certain what it's not."

Understanding these lizards' evolutionary history and adaptive tricks is interesting on its own merits, but it may also yield insights into regenerative medicine. Animals that casually toss out and regrow body parts are a boon to scientists who hope to replicate similar processes in human patients suffering from loss of cells, tissues, or even whole organs. So when it comes to deciphering the mysteries of fish-scale geckos, even people have skin in the game.

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