When researchers first laid their hands on a newly discovered frog deep in Panama’s forests, they were in for a surprise. The small, golden amphibian left a lasting impression—literally. As they handled the frog, its bright yellow pigment rubbed off onto their skin, leaving their fingers stained with the same hue that gives this remarkable species, Diasporus citrinobapheus, its name.

The species was found deep in the mountains of western Panama in 2012. The small golden frog, D. citrinobapheus, belongs to the family Eleutherodactylidae and was described in a study. Its name—derived from the Greek words for “citrus-yellow” and “dye”—refers to its vivid coloration, which even stains the fingers of those who handle it.

“When we finally caught the first individuals by hand, we noticed that it dyes one’s fingers yellow when it is handled,” researcher Andreas Hertz said. “The scientific name (Diasporas citrinobapheus) of this new frog refers to this characteristic and means yellow dyer rain frog.”

Males measure between 17.3 and 19.7 mm in length, making them tiny compared to other frogs in the region (about the size of a coin). Females, on the other hand, grow slightly larger, reaching about 21.8 mm in length. Its small size, coupled with its high-pitched call, makes D. citrinobapheus a difficult species to locate and monitor. In fact, after its discovery in 2012, not much has been published about it at all.

One of the key distinguishing characteristics of Diasporus citrinobapheus is its vocalization. Unlike the sharp “tink” calls common to other species in its relaties, D. citrinobapheus emits a whistle-like call. This call is not just different in sound but also in its structure: it consists of individual notes organized into call groups, with each group containing between eight and seventeen calls. These whistles can be heard primarily after dusk, as males seek to attract mates from their perches high in the dense vegetation.

Colorful, but it’s not clear why

The species’ vivid coloration also sets it apart. D. citrinobapheus sports a bright yellow or orange dorsal surface, sometimes accompanied by dark blotches or spots. Its belly, however, is mostly translucent, offering a view of its inner organs, with a few scattered spots of white. This remarkable coloration not only makes it a standout among frogs but also raises questions about its potential role in the animal’s defense mechanisms.

Interestingly, when handled, D. citrinobapheus can leave behind a yellowish stain on human skin. Researchers have theorized that this coloration might serve as a defense against predators, possibly by being unpalatable or otherwise signaling toxicity. However, when tested for alkaloids, the chemical compounds responsible for toxicity in many amphibians, no such substances were detected. This leaves researchers to wonder whether the frog’s unique pigmentation is simply an evolutionary quirk rather than an active defense.

“We cannot say whether the dye is any good as a predatory defense, as we could not find any poisonous components,” says Hertz. “Maybe the color is just easily washed out and has no particular function. However, for now, this peculiarity of the new species remains enigmatic.”

A new species already under threat

The natural habitat of Diasporus citrinobapheus is the intermediate elevations of the Cordillera Central, where the species is found at altitudes between 680 and 790 meters above sea level. The region is characterized by dense forests, a mixture of primary and secondary growth, as well as agricultural areas like plantations. Unlike some amphibians that are closely tied to pristine environments, D. citrinobapheus appears adaptable, thriving not just in untouched forests but also in disturbed areas.

While the discovery of new species like Diasporus citrinobapheus is cause for celebration, it also serves as a stark reminder of the challenges facing amphibians in Central America. Many of Panama’s amphibians are already endangered, and there’s a good chance this yellow frog can become endangered in the future as well. Without proper conservation measures, even newly discovered species may be at risk of extinction.

In the meantime, Panama’s forests remain a treasure trove of biodiversity. Who knows what exciting new species scientists will find next?

The study “An integrative approach to reveal speciation and species richness in the genus Diasporus (Amphibia: Anura: Eleutherodactylidae) in eastern Panama” was published in the journal Zoological Journal of the Linnean Society.