It is orange, fluorescent and miniature in size. Meet the newly discovered amphibian Brachycephalus rotenbergae, a species of pumpkin frog found in the Atlantic Forest of Brazil.
The animal belongs to a family of at least 36 pumpkin frogs, which are named after the popular Halloween pumpkins. Like poisonous frogs, their vibrant colors are likely a signal to predators that their skin carries a potentially deadly toxin.
The new species, described recently in the magazine PLOS ONE, was discovered during extensive research efforts in Brazil to find new pumpkin cucumbers. Identification of the creatures is crucial for the conservation of Brazil’s biodiversity, especially in species-rich areas such as the Atlantic Forest, which has lost 93% of its original cover due to deforestation and agriculture, experts say.
Brazil has the largest number of amphibians in the world ̵
“The best time to be a scientist is when you’re looking at something new and you’re the only person who knows,” said study leader Ivan Sergio Nunes Silva, a herpetologist at Sao Paulo State University.
“Unfortunately, nowadays we are losing unidentified species faster than we can describe new ones.”
The tale of a new frog
Nunes and his team found him B. Rothenberg during 76 field surveys between 2018 and 2019 in the 6,500-foot-high Monteiro Mountains, spending hours in wandering rocky outcrops and streams that flow through the woods.
Back in the lab, the team took DNA samples from the new toad and compared them to samples from famous pumpkin frogs. They also analyzed his physical characteristics and bone structure, his behavior and records of his calling to mate to determine that it was a new species.
For example, the new pumpkin frog is smaller than other known frogs, with a smaller snout. Other unusual features include black, faded skin patterns and a preference for the higher heights of the Atlantic Forest. (See beautiful photos of amphibians around the world.)
The creatures also cannot hear the sound of their own call because their ears are underdeveloped, Nunes said.
“Their communication is essentially visual,” he added, as frogs probably communicate through gaping mouths.
Mysterious amphibians also glow when placed under ultraviolet light – a wavelength that they can see but humans cannot. It is known that only two other types of pumpkin cucumbers fluoresce, he added. (Read about squirrels that “glow” in pink.)
The comprehensive approach of Nunes and colleagues – the study of the physical body, genetics and amphibian appeals – is important, especially in the case of species that are similar, says Michel Varagio Garey, a professor at the Institute for Latin American Incident Ciências da Vida e da Natureza, in Foz do Iguazu, who did not participate in the study.
Such an in-depth method could “reveal a still unknown diversity,” he says, and possibly recategorize some species that have been mislabeled.
In fact, until this study, B. Rothenberg was wrongly categorized as very similar in appearance B. epipium, the authors say – although this reclassification is also a source of controversy among some amphibian researchers.
For example, Rute Clemente-Carvalho, head of the Genomics Laboratory at the Hakai Institute in British Columbia, Canada, is not convinced that B. Rothenberg is a new species, but rather B. epipium. On the one hand, she says the genetic differences between B. epipium and B. Rothenberg outlined in the study are very small.
In addition, the researchers made most of their genetic comparisons between B. Rothenberg and remotely connected pumpkin cucumbers and not enough with B. epipium samples to say it’s a new species, says Clemente-Carvalho by email.
Although the study is very useful for continuing research on pumpkin cucumbers, she says she would like to see further analysis for comparison. B. epipium and B. Rothenberg.
A lot of work needs to be done
The population of the new species is unknown, but Nunes and colleagues hope to conduct more research to find out where it lives – as well as to look for more species of pumpkin frogs.
The rest of the Atlantic forest is protected mainly in nature reserves, but parts are still threatened by deforestation, climate change and land use change. Although the rate of deforestation is declining in Brazil, more than 28,000 acres of land were cleared in 2018.
Nunes hopes the discovery will inspire the government and organizations to take better care of their resources, such as closely monitoring endangered species.
“Nature is only stable if it’s complex enough,” says Nunes. “Describing biodiversity is paramount for a mega-diverse country like Brazil.”