This Glass Frog’s Heart Is Visible Through Its Skin

The new species of frog has a transparent underside, offering a glimpse of its beating heart inside

Glass Frog
Hyalinobatrachium yaku Jaime Culebras and Ross Maynard

Glass frogs are pretty remarkable creatures. Of the 150 species, many have transparent abdomens that give viewers a glimpse into their inner workings—guts, heart and all. Now, as Mindy Weisberger reports for Live Science, a new species has joined their delicate ranks. And it's even more translucent than the rest.

The species, dubbed Hyalinobatrachium yaku, is just two centimeters long and sports markings similar to other glass frogs in the region. So identifying the new species was far from easy; researchers used a combination of the frog's unusually long call in the wild and DNA tests conducted back in the lab, Lou del Bello reports for New Scientist. The researchers identified three populations of H. yaku in three separate areas in the Amazonian lowlands of Ecuador, detailing their find this week in the journal ZooKeys 

“I work with frogs every day and this is one of the most beautiful species I have ever seen,” Juan Guayasamin, researcher at Ecuador’s Universidad San Francisco de Quito, tells del Bello. Though the glass frog appears similar to its relatives, its dark green spots and extra large transparent patch sets it apart.

But the new species is also unusual in other ways. Glass frogs are known to cling to the undersides of leaves that overhang small rivers and streams while guarding clutches of eggs. When the tadpoles hatch, they drop into the stream below. And that's just what the researchers found at two of the locations. But in the third population, some 70 miles away, the frogs all seemed to prefer hanging out in shrubs and on ferns several inches above the ground—and roughly 90 feet from the nearest waterway.

It’s likely that the new frog has an even wider distribution than the three places the scientists have found so far, extending all the way into Peru. But it’s also possible, the researchers note, that the newly discovered creature may already be threatened or endangered. Glass frogs of every species require large undivided tracts of forest to survive, and roads can act as barriers.

But researchers can't yet say how the latest glass frog is faring. “We do know...that its habitat is rapidly disappearing. Oil production has expanded greatly in this species’ range, and road building is rampant,” Paul Hamilton, founder the non-profit Biodiversity Group tells del Bello.

According to a press release, it is often difficult to determine the range of glass frogs and other small amphibians. These tiny creatures are difficult to find in the wild. And don't count on easily identifying many previously collected critters in museums—preservation methods often destroy distinguishable markings like color and spots.

But that doesn't mean scientists aren't looking. Del Bello reports that between 100 and 200 new species of amphibian are discovered each year. In 2015, researchers in Costa Rica identified another new type of glass frog that looks remarkably like Kermit.

Though scientists can't say for sure if the creatures are in trouble, Hamilton hopes this latest find can raise awareness of the dangers of fossil fuel extraction in the Amazon. And if the abstract threat of losing these creatures isn't enough to make you care, take another look at the glass frogs. Their tiny, visibly beating hearts may just make you feel something in yours.

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