A new species of poison dart frog, so tiny it can fit on a fingernail, has been discovered in a rainforest in Panama, a new study says. (Photo : Cesar Jaramillo, Smithsonian Tropical Research Institute)

A new species of poison dart frog, so tiny it can fit on a fingernail, has been discovered in a rainforest in Panama, a new study says.

Scientists found the mini-amphibian, distinguished by its unique call and smooth, orange-colored skin, in Rio Caño in the district of Donoso, Colón Province, Panama, according to a study published in the journal Zootaxa.

Measuring just 12.7 millimeters in length, the newly described Andinobates geminisae remains something of a mystery, researchers say.

For one, its electric-orange color makes the frog look nothing like its closest genetic relatives in the region.

"The new species superficially looks much more like the strawberry poison dart frog (Oophaga pumilio)," study co-author Andrew Crawford, a professor of evolutionary genetics and biostatistics at the University of the Andes in Colombia, told National Geographic. "Perhaps A. geminisae had been observed previously but was confused with Oophaga."

But once Crawford, along with researchers from the Smithsonian Tropical Research Institute and the Universidad Autónoma de Chiriquí in Panama, sequenced the frog's DNA, it was confirmed that this was a new species of Andinobates.

"They've known it was there for several years. However, they were not sure if it was only a variety of another poison dart frog species, Oophaga pumilio, which exhibits tremendous color variation," Cesar Jaramillo, a Smithsonian herpetologist, said in a statement. "Based on morphological characteristics of the adult and the tadpole, I thought it might be a new species of Andinobates."

Because this new frog species appears to be only found in a tiny part of Panama, habitat loss is a major threat to its existence. The researchers, therefore, recommend the formulation of special conservation plans to guarantee the survival of the species, which is also sought after by those in the pet trade.

"It is important we save some of this frog's tiny habitat to be able to study this unusual species more," Crawford told National Geographic.