4 new tooth-frog species discovered in West African forests

Until last year, only one tooth-frog species had been identified within the Upper Guinea forests of West Africa, a region that stretches across parts of Guinea, Sierra Leone, Liberia, Cote d'Ivoire, Ghana and Togo.

But a new paper suggest the lone species is actually a family, complete with speciation. In a new issue of the open-access journal Zoosystematics and Evolution, researchers announced the discovery of four new torrent tooth-frog species -- all highly endangered.

The aforementioned lone species is Odontobatrachus natator is easy to differentiate from other West African torrent frogs, but difficult to separate from its closest relatives. But new molecular analysis by researchers in Germany revealed distinguishing morphological characteristics that necessitated the new species designation. The single species is a family, a family with species variation.

The saber-toothed frogs are named for their unusual jawbones which boast tusk-like appendages on the lower jay, as well as curved upper teeth. The nocturnal frogs prefer the cool, running waters of forest streams.

The team of scientists who discovered the species was led by Michael F. Barej, a researcher with Berlin's Humboldt-Museum.

With so much rapid change in scientists understanding of these rare frogs, Barej and his colleagues aren't taking anything for granted.

"Recognition and description of species is just a first step which provides the baseline for subsequent studies to gather further data on the ecology or behavior -- or simply: naming does not mean knowing a species," researchers wrote in their new paper on the discovery.

Up until last year, Upper Guinea's torrent frogs were grouped in with the genus Petropedetes, which includes a host of Central African frogs. But a 2014 study found the frog warranted its own genus. Now, researchers have shown the frog to be part of a diverse family of five -- albeit a family facing a range of environmental threats.

"West African torrent-frog species are at risk of becoming extinct because of habitat loss in the Upper Guinean biodiversity hotspot, whose 'true' biodiversity is still far from being completely known," scientists wrote.

Researchers say they hope to continue to their work in Upper Guinea, as it continues to reveal an array of biological secrets.

"Although West Africa, defined as ranging from Senegal to Nigeria, is regarded as one of the better known regions on the continent, more than ten new amphibian species have been described in the last decade, and more await formal description."