Newly described gecko from Madagascar a master of disguise

  • Madagascar is a hotspot for gecko diversity, and the latest to appear on the tree of life is Uroplatus garamaso.
  • U. garamaso, with a length of 8.3-13.9 cm (3.3-5.5 in), is one of the larger leaf-tailed lizards inhabiting the island, but is still a master at hiding in plain sight.
  • The gecko’s known range is restricted to the forests in the north of the island: Montagne des Français, Montagne d’Ambre, and Ankarana in the Diana region.

The leaf-tailed geckos of the genus Uroplatus aren’t easy to find. In the jungles of their native Madagascar, this is certainly true, owing to their remarkable ability to meld into their surroundings. But scientists are still uncovering species from the island nation with astonishing regularity by disentangling species complexes using DNA analysis.

In 1989, only six of these leaf-tailed geckos were known to science from Madagascar. Today, that number is 22. The latest to appear on the tree of life is Uroplatus garamaso. These cryptic creatures can’t always be differentiated on sight from their close cousin, U. henkeli.

“The large genetic divergence in both mitochondrial and nuclear markers was the most important trait to distinguish both species,” said Frank Glaw, a herpetologist who led the team from the Bavarian State Collection of Zoology, or ZSM, in Germany. They documented their find in a new paper in the journal Salamandra.

U. garamaso is an expert camouflager. Drag the slider to the left to reveal the gecko on the branch. Images courtesy of Mark D. Scherz/Natural History Museum of Denmark..

More than 85% of Madagascar’s wildlife is unique to the island nation, and more endemic species are described every year. The Gekkota suborder of lizards, which already boasts more than 80 species from Madagascar, is one of the most prolific. In 2022, one study alone described eight species new to science.

The reptiles come in all sizes in Madagascar. U. garamaso, with a length of 8.3-13.9 centimeters (3.3-5.5 inches), is one of the larger geckos inhabiting the island. The tiniest ones are a little more than an inch. Even though it’s relatively large, U. garamaso is still a master at hiding in plain sight, doing so by imitating tree bark. “For this purpose, they have skin fringes along the head and body and a flattened tail. During daytime, they press their body on the branches and become almost invisible,” Glaw said.

Their endeavor to remain unseen is helped by the fact that most leaf-tailed geckos are nocturnal, so their daytime activity is limited. They also have excellent night vision; in low light, geckos can see 350 times better than humans.

There are subtle differences in the physical traits of U. garamaso and U. henkeli; the former is smaller in size and its tail is narrower, while the latter sports blackish pigmentation at the tip of its tongue, which U. garamaso lacks. The new species also has striking yellow-reddish irises, and the structure of its hemipenis, the male reproductive organ, is different from that of U. henkeli.

“This study adds to the species diversity of one of the most fascinating genera of Malagasy squamates and further affirms the high degree of regional endemism in northern Madagascar,” the study authors wrote.

Distribution map of <i>U. henkeli</i> and <i>U. garamaso</i>.
Distribution map of U. henkeli and U. garamaso. U. henkeli is found across a wider area, from Tsingy de Bemaraha in the west to Nosy Be in northern Madagascar. U. garamaso’s habitat includes both humid and dry forests.

U. henkeli is found across a wider area, from Tsingy de Bemaraha in the west to Nosy Be in northern Madagascar. The known range of its newly described cousin is restricted to the forests in the north of the island like Montagne des Français, Montagne d’Ambre, and Ankarana in the Diana region and in the neighboring Sava region.

U. garamaso’s habitat includes both humid and dry forests. A section of the woodland is protected under Malagasy law, but logging and forest fires are a grave threat in areas outside these reserves. Between 2002 and 2022, the Diana region lost 15% of its primary rainforest, according to data from Global Forest Watch.

One of the challenges of saving species from this biodiversity hotspot is their limited ranges. When the habitat in one corner of the island starts to disappear, the entire species is at risk of vanishing from the planet.

Banner image: Uroplatus garamaso. Image courtesy of Jörn Köhler/ Hessisches Landesmuseum Darmstadt, Germany.

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Citation:

Glaw, F., Köhler, J., Ratsoavina, F. M., Raselimanana, A. P., Crottini, A., Gehring, P.-S., … Vences, M. (2023). A new large-sized species of leaf-tailed gecko (Uroplatus) from northern Madagascar. Salamandra, 59(3), 239-261. Retrieved from https://www.salamandra-journal.com/index.php/home/contents/2023-vol-59/2125-glaw-f-j-koehler-f-m-ratsoavina-a-p-raselimanana-a-crottini-p-s-gehring-w-boehme-m-d-scherz-m-vences/file