Geckos that shed skin to escape foes discovered

Scientists have discovered a new species of geckos that can easily shed all of its skin under attack, leaving its predator with a mouth full of large scales.
The species, dubbed Geckolepis megalepis, possesses the largest scales of any gecko.
The large scales are attached by relatively narrow region that tears with ease, and beneath them fish-scale geckos have a pre-formed splitting zone within the skin itself.
Although several other geckos are able to lose their skin like this if they are grasped really firmly, Geckolepis are apparently able to do it actively, and at the slightest touch.
While others might take a long time to regenerate their scales, fish-scale geckos can grow them back, scar-free, in a matter of weeks.

"A study a few years ago showed that our understanding of the diversity of fish-scale geckos was totally inadequate," said Mark D Scherz from Ludwig Maximilian University of Munich (LMU Munich) in Germany.

"It showed us that there were actually about thirteen highly distinct genetic lineages in this genus, and not just the three or four species we thought existed," said Scherz.
"One of the divergent lineages they identified was immediately obvious as a new species, because it had such massive scales," he said.
"But to name it, we had to find additional reliable characteristics that distinguish it from the other species," he said.

One of the main ways reptile species can be told apart is by their scale patterns, but these geckos lose their scales with such ease that the patterns are often lost by the time they reach adulthood.
"You have to think a bit outside the box with Geckolepis. They are a nightmare to identify. So we turned to micro-CT (micro-computed tomography) to get at their skeletons and search there for identifying features," Scherz said.
Micro-CT is a 3D x-ray of an object. This method allows morphologists to examine the skeletons of animals without having to dissect them.
By looking at the skeletons of the geckos, the team was able to identify some features of the skull that distinguish their new species from all others.

Geckolepis megalepis is most remarkable because of its huge scales, which are by far the largest of any gecko.
The researchers hypothesise that the larger scales tear more easily than smaller scales, because of their greater surface area relative to the attachment area, and larger friction surface.
"What is really remarkable though is that these scales - which are really dense and may even be bony, and must be quite energetically costly to produce - and the skin beneath them tear away with such ease, and can be regenerated quickly and without a scar," said Scherz.
The mechanism for regeneration, which is not well understood, could have applications in human medicine.

The study was published in the journal PeerJ.