Eight tiny new gecko species, smaller than a human finger, discovered and named in Madagascar

Madagascar is a wilderness of stunning natural beauty and unique plants and animals found nowhere else on Earth. The island can now lay claim to eight new species of gecko described for the first time by scientists.

The international team of researchers published their findings in the journal Zootaxa.

Madagascar’s lush rainforests – famously home to fossa, pygmy chameleons, giant hissing cockroaches, tortoises and many lemurs – are rich hotbeds for studying animals and their evolution. Researchers have been surveying Madagascar’s geckos for decades, including the tiny brown Lygodactylus geckos in the subgenus Domerguella.

From the get-go, they have been trying to understand the geckos’ distribution and evolution from the assumption that there were just five species.

Seven of the new species of dwarf geckos described from Madagascar. Credit: P.-S. Gehring, H.-P. Berghof, M. Vences & M.D. Scherz.

But new DNA analysis and examination of the animals’ scales has led the scientists to believe there may be as many as seventeen. Eight new species have been named in the journal paper. In some places, as many as three or four species were found sharing the same locale.

“This was a remarkable discovery,” says first author Professor Miguel Vences of the Technische Universität Braunschweig, Germany. “On Montagne d’Ambre in the north of Madagascar we thought we were collecting just one species, but now we find there are four. Four different, closely related species that are almost indistinguishable to us, occurring together in the same place, apparently without interbreeding – this is exceptional, even for Madagascar.”

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There are more than 300 species of reptile known to live in Madagascar. Of those species, more than 90 percent are endemic and 36 of the 64 genera found on the island are found nowhere else.

Having evaded detection for so long, it’s no surprise that many of the new reptile and amphibian species found in Madagascar recently have been tiny. The new geckos are no exception.

Domerguella are tiny, at just five to seven centimetres from the nose to the tip of the tail,” says senior author Dr Mark D. Scherz, Curator of Herpetology at the Natural History Museum of Denmark. “We think that their small size may play a role in the way they speciate because small animals are generally less able to move from one area to another, and are more likely to get isolated by barriers like rivers cropping up between populations. This could explain why we have seen these kinds of patterns in the tiny frogs, chameleons, and now also geckos that we have been studying in Madagascar.”

The new findings also shed light on how some species are at risk of extinction before we know they even exist.

“The five species we knew before were mostly thought to be unthreatened, but the eight new species are all either probably endangered or critically endangered,” says Dr Fanomezana Ratsoavina, manager of the Unit for Zoology and Animal Biodiversity at the University of Antananarivo in Madagascar. “This shows how important it is to continue to work to discover, describe, and assess the conservation status of the wildlife of Madagascar.”

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