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Two new frog species discovered in remote Madagascar rainforest

  • Both frogs belong to a group under the genus Rhombophryne characterized by small, fleshy spines over their eyes, but have fewer spines above each eye than any other member of the group.
  • One of the scientists that discovered the frogs called them “another example of the great diversity of animals in tropical areas that have yet to be described before many of these areas disappear as a result of the deforestation suffered by tropical regions, especially Madagascar.”
  • Madagascar is thought to be home to as many as 500 species of frogs found nowhere else on Earth, many of them as understudied as they are threatened.

Two new species of frog have been discovered in Madagascar’s Tsaratanana Massif, one of the island nation’s most remote regions.

Both frogs belong to a group under the genus Rhombophryne characterized by small, fleshy spines over their eyes. But according to a paper describing the new species published in the journal Herpetologica, Rhombophryne ornata and Rhombophryne tany have fewer spines above each eye than any other member of the group.

R. ornata is also unusual, the authors of the paper write, in presenting a reddish color and having “fairly elaborate” dorsal markings as well as a black mark between each eye and on its back. It was given the name ornata due to its color and decorative features.

R. tany, on the other hand, does not have any characteristics that readily distinguish it from other species in the same group. The scientists had to use a molecular analysis of R. tany to prove it was unique. The name tany actually means “land” or “ground” in the local language, which not only references the frog’s brownish color but also the fact that it spends most of its time on the ground.

In fact, both species are somewhat difficult to find in the wild because they live on the forest floor, where they blend in with fallen leaves, according to David Vieites, a scientist at the National Museum of Natural Sciences in Madrid, Spain and one of the authors of the Herpetologica study.

Vieites and team, a group of scientists from Germany and Spain, believe R. ornata and R. tany may be “sister” species, since Micro-CT scans revealed common differences between their skeletons and other members of their group of close relatives.

Rombophryne ornata received its name owing to its color and decorative features. It can be told apart from other frogs of the same genus by the reddish color it presents. Photo by Miguel Vences.

Discovering the two new species is “another example of the great diversity of animals in tropical areas that have yet to be described before many of these areas disappear as a result of the deforestation suffered by tropical regions, especially Madagascar,” Vieites said in a statement.

Scientists appear to be working overtime to describe all of the species they can find while there’s still time (lucky for them that 10-pound, dinosaur-eating Malagasy frog went extinct 65 to 70 million years ago). Madagascar is thought to be home to as many as 500 species of frogs found nowhere else on Earth, and many of them are understudied as well as threatened.

For instance, a 2012 study at a nature reserve on Madagascar’s east coast, one of the last surviving lowland forests in the country, found 76 different frog species living in a single forest, 36 of which were believed at the time to be previously unknown to science. And that forest was tiny: only about half the size of Manhattan. There are less than 90 species of frogs found in all of North America.

Not all of the understudied species out there live in nature reserves, of course — but then, living in a protected forest doesn’t guarantee a species’ longevity, either. Last year, a new skeleton frog was discovered in Madagascar that already qualified to be listed as Critically Endangered on the International Union for Conservation of Nature (IUCN) Red List because it was relegated to a single patch of forest that was still facing severe threats despite its protected status.

New species in Tsaratanana Massif already threatened

The rainforests in the northern part of the island of Madagascar are rich in biodiversity, yet a relatively small number of species living there are known to science. Discovering new native species is a difficult task, according to Vieites, because gaining access to the remote, mountainous Tsaratanana Massif region, the site of Madagascar’s tallest peak, is not easy.

“Those mountains are home to a high level of native species and are very rarely visited by researchers seeing as there are no roads — and barely any paths — that lead to the base,” Vieites said.

The rainforests in Tsaratanana Massif, at the north end of the island of Madagascar, are highly fragmented. In the Herpetologica paper, Vieites and his team write that R. ornata and R. tany, newly discovered though they may be, already qualify for the IUCN’s Red List.

“As these species have a limited extent of occurrence, and are known only from a single location in a forest that is declining in quality, we propose they be listed as Vulnerable B1ab(iii) on the [IUCN] Red List,” they wrote.

Luckily for the two species, however, the area where they were discovered is a national park that is very difficult to access. “We hope that this area will remain pristine for a long time,” Vieites said.

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