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| Photo: The newly discovered Ecuadorian rain frog. Credit: Juan M. Guayasamin/Universidad San Francisco de Quito |
"It has a yellow dorsum [back] with black stripes," he told Seeker. "Its iris varies from light blue to grayish green."
The frog is a newly identified species that Guayasamin and colleague Chris Funk of Colorado State University have named Pristimantis ecuadorensis, the Ecuadorian rain frog. They describe it in the journal PLOS ONE.
"The discovery is surprising, mostly because of the colorful nature of this species," Guayasamin said. "Often times, the most beautiful species are readily recognized and described. The description of P. ecuadorensis is an exception to this rule."
The unique find occurred while he and Funk were performing genetic sampling of frogs from sites while crisscrossing the western slopes of the Ecuadorian Andes. Ecuador is ringed by a Pacific coastline, the Amazon basin in the east, and the Andes Mountains in the middle. DNA sequencing allowed the researchers to confirm that their spectacular frog, which hails from the Andes Las Pampas region, is indeed a new species.
The frog lives in a cloud forest, which is a moist tropical or subtropical forest characterized by persistent low-level clouds.
Usually distance or geographical barriers can lead to speciation. For example, a river or mountain range dividing two populations can limit gene flow, allowing species to evolve new traits over millions of years. Uniquely, the Ecuadorian rain frog appears to have become a distinct species in the absence of such geographical barriers.
The researchers suspect that environmental differences led to the speciation. A close relative of the Ecuadorian rain frog, the ornate rain frog (Pristimantis ornatissimus), lives nearby, but in a lower elevation habitat.
"What we observed is that P. ecuadorensis is found at higher elevations than P. ornatissimus," Guayasamin said. "Thus, it is possible that the new species has adapted to colder microhabitats."
He added that mysteries still surround the Ecuadorian rain frog. He and his colleagues, however, have thus far determined that the frog is relatively small, with males measuring just under an inch long and females measuring about 1.5 inches long. The frog is nocturnal, perhaps helping to explain how it went undetected by humans until now.
The frog additionally is a "direct developer," which means that it lacks a tadpole stage.
"Eggs are placed in humid places out of water and directly develop into minute froglets," Guayasamin explained.
The research team analyzed the frog's fecal samples and found the remains of beetles, crickets, and spiders, revealing the colorful amphibian's diet.
Although just discovered, the frog is already considered to be highly endangered. Its population appears to be small, and its habitat is threatened by agriculture and livestock, mostly cattle, which are raised in the region.
"We think that the discovery is important because, hopefully, it will draw attention to an area of Ecuador that is under considerable human pressure," Guayasamin said. "Conservation efforts are badly needed!"
The Ecuadorian rain frog is not the first new frog species to be discovered by Guayasamin and Funk. In 2009, they discovered a coffee-colored frog with distinctive elongated, slender toes. They named it Pristimantis bicantus.
The scientists' work in studying South American wildlife has resulted from close international collaborations between Ecuador universities and organizations and three US universities: Colorado State University, George Washington University, and the University of Kansas.
Such partnerships are important, Guayasamin said, "especially in these times when important political figures work to build walls between us."
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