Connect to share and comment

In world of amphibians, a rare bright spot

Scientists find a new species of frog in Costa Rica.

SAN JOSE — Global amphibian news tends to be a downer. Acutely vulnerable to the slightest environmental change, frogs, toads and salamanders are too often described as "disappearing."

But a recent surprise appearance has given scientists something to leap about.

A team from the University of Costa Rica (UCR) recently encountered a new species of dink frog in the Cordillera de Talamanca mountains near the border with Panama. The frog is believed to be endemic to this country, adding a new, roughly 2-centimeter-long member to the nearly 200 types of amphibians known to inhabit Costa Rica. This little nation ranks 19th in the list of countries with the most amphibian species, according to the International Union for Conservation of Nature (IUCN).

The discovery came about like this: Scientists were helping to train local farm workers who want to increase their knowledge of nature in order to secure jobs as tour guides through Costa Rican national parks. During a tour through the jungle of a high elevation valley called Valle del Silencio, on the mountain range's Caribbean slope, the group heard a whole lot of croaking going on.

"When we arrived at Valle del Silencio we rested up and then took a midnight hike. With flashlights, we went walking and looking around, and suddenly, amid a bromeliad — one of those plants we have in our forests that looks like a pineapple growing out of the ground — we found a female, which is the black one of this species," UCR scientist Gerardo Chavez explained."When I saw the color I immediately said, 'this is a new species.'

"It was a night of celebration for all the students," he said.

Following confirmation through genetic analysis, Chavez and fellow scientists at UCR co-authored a report on the discovery in Zootaxa, an international journal for animal taxonomists. Not only is this frog unique to Costa Rica, they say, but it appears to be endemic to the very valley in which it was spotted.

The dink or tink frog, of the genus Diasporus, is known by a perhaps more flattering name in Spanish: "rana campana" — or bell frog — "because their song is like a little bell," Chavez said, with fondness. Costa Rica was previously thought to be home to four of the eight species of Diasporus, he said. The newly encountered one would make that five out of nine.

Dubbed Diasporus ventrimaculatus, the frog has several remarkable features that distinguish it from the rest of the family. First, it likes a bit of altitude. The species was spotted at about 2,500 meters (8,202 feet), where average temperatures are about 17 degrees Celsius (62.5 degrees Fahrenheit) — quite cool for a frog in the tropics. Other dink species normally dwell below 2,000 meters (6,651 feet), and most don't crawl above 500 meters (1,640 feet), Chavez said.