Surprising Inner-City Frog Among 7 New Species Found in Asia

Newfound golden-backed frogs had likely been overlooked by scientists.

The large golden-backed frog (Hylarana magna) is nearly four inches long.

PHOTOGRAPH BY SD BIJU, SYSTEMATICS LAB

James Owen

for National Geographic

PUBLISHED OCTOBER 29, 2014

Seven new species of golden-backed frogs have been discovered in Sri Lanka and India—including one in the middle of a bustling city, a new study reports.

Scientists caught the urban golden-backed frog(Hylarana urbis) in a weed-choked lake surrounded by a concrete jungle of factories, hotels, and businesses inKochi (map), a city of 2.3 million in India.

The surprising new species, which dwells in ponds and overgrown waterways, is known to exist only in two urban settings, said study leader Sathyabhama Das Biju, an amphibian researcher at the University of Delhi.

But that doesn't mean H. urbis is cut out for city life, according to Biju, whose numerous past finds in India include the extraordinary purple frog. (See "Weird Purple Frog Seduces Females From Underground.")

"I cannot really say that they have adapted to live in urban areas—probably not," he said.

Instead, the frogs may have lived there before their habitat was developed—and despite appearances, "urbanization could be putting them into danger."

Scientists discovered the urban golden-backed frog (Hylarana urbis) in the middle of a big city in India.

PHOTOGRAPH BY SD BIJU, SYSTEMATICS LAB

Forgotten Frogs

The frog's discovery comes from a ten-year survey of golden-backed frogs in the Western Ghats—a biologically rich mountain range that runs down the western side of India—and the whole island of Sri Lanka. (See pictures of more frogs found in western India, including the meowing night frog.)

The findings, published October 29 in the journal Contributions to Zoology, suggest that golden-backed frogs, with a range that stretches from Africa to Australia, are much more diverse than had been thought.

Based on an analysis of the physical and genetic characteristics of golden-backed frogs, the study found that populations in the Western Ghats and Sri Lanka had erroneously been lumped together by scientists—and that they actually represent six new species for India and one for Sri Lanka. That increases the known species of golden-backed frogs from 84 to 91. (See "14 New 'Dancing Frogs' Discovered in India.")

The reason for past misidentification was that, superficially at least, golden-backed frogs look alike. Even so, Biju said, it isn't really that hard for scientists to tell them apart.

"I think it's because of a lack of attention," he added.

The Sri Lankan species, Hylarana temporalis, for example, is easily distinguished by a ridge of skin behind the eye, Biju noted. The shape of the tips of the fingers and toes, and the degree of webbing on the hands and feet, also helped the team to sort the frogs apart from the new species in the Western Ghats, which were misidentified as H. temporalis for a long time.

The study then used DNA "molecular support to prove that the species in both these regions are clearly distinct," Biju said.

Big Haul

The new-species haul also included the largest golden-backed frog known from either country.

Dubbed Hylarana magna, or large golden-backed frog, it measures up to 3.6 inches (9.2 centimeters) long. Most adult golden-backed frogs are less than 1.6 inches (4 centimeters) long.

Recorded as seen in just a handful of sites in the southern Western Ghats,H. magna was found next to fast streams in dense evergreen forest.

However, Biju and colleagues note that many golden-backed frogs "are hanging on precariously in highly threatened habitats"—like the streetwiseH. urbis. (See pictures of vanishing amphibians in National Geographicmagazine.)

"If the present trends in extinction continue," Biju warned in a statement, "many frogs could disappear forever."