20 frogs in one go Several new frog species discovered on Madagascar

Biologists are working against the clock as our planet’s biodiversity dwindles: Many fascinating organisms will disappear from the face of the earth without their existence ever being known. Only their discovery enables research into their distribution and conservation. An international team led by Professor Miguel Vences from Technische Universität Braunschweig has now made a huge stride towards a better understanding of the diversity of amphibians. In the rainforest of Madagascar, the researchers discovered no less than 20 new species of frogs and report on their findings in the journal “Megataxa”.

The newly discovered frogs all belong to the subgenus Brygoomantis, which is only found on Madagascar, an island nation off the south-eastern coast of Africa. Until now, only a little more than a dozen species were known from this subgenus of frogs – now there are 35. These inconspicuous brown frogs are very common in Madagascar’s rainforests, but the different species are difficult to distinguish at first glance. For this reason, it was necessary to include modern molecular genetic methods in the work.

Comparison with specimens from the museum

Using so-called “museomics” approaches, it was also possible to check the DNA of old specimens from zoological collections. “These old museum collections were often considered dusty and outmoded. Now we understand that they are enormously important archives of global change,” says Professor Miguel Vences. “The good news from our study is that none of the frog species described from Madagascar over the last 200 years has gone extinct. The bad news is that many of these species have such small ranges that the disappearance of even the smallest forest fragments could mean their permanent extinction,” Vences continues.

Calls like a creaking door

As with most frogs, the males of Brygoomantis emit advertisement calls to attract females, and these calls differ between species. It was these mysterious-sounding calls that put Dr Mark Scherz of the Natural History Museum in Copenhagen, Denmark, the lead author of the study, on the trail of the new species: “The calls typically sound like a creaking door or a gurgling stomach. Only after we were able to catch the hidden calling individuals of these frogs with a lot of patience did we understand that there is often not one species, but up to five different species of Brygoomantis at a stream.”

The team collected data over a long period of time for this work. “This study is also the culmination of decades of field research,” said Dr Frank Glaw from the Zoologische Staatssammlung München in Munich. “Our dataset consists of genetic data from over 1300 frogs, and measurements of several hundred specimens.”

However, even after this extensive research, the last word on Brygoomantis frog biodiversity has not yet been said. “There are still several Brygoomantis lineages that may represent seperate, new species, but that we do not have enough data for,” says Dr. Andolalao Rakotoarison, biologist and co-chair of the IUCN’s Amphibian Specialist Group for Madagascar. “Even for those species for which we have names, we know almost nothing about their biology and ecology. We urgently need more field research, especially in areas that are difficult to access, in order to be able to plan conservation concepts in a scientifically sound way.”