'Extinct' tree frog genus rediscovered in India after 137-year absence

NEW DELHI, Jan. 21 (UPI) -- A group of tree frog species scientists thought had gone extinct has turned out to be rather abundant in India and elsewhere in Asia.

The golf ball-sized frogs were rediscovered by renowned Indian biologist Sathyabhama Das Biju. Biju is known in India, and by his fellow amphibian experts, as "The Frog Man."

In 1870, English scientists collected a pair of odd-looking tree frogs in India. The specimens were brought back for study at the Natural History Museum in London. But researchers failed to find any of their friends in the wild, and it was assumed the frogs belonged to a group of extinct amphibians. They named the species Polypedates jerdonii.

But a team of researchers led by Biju have shown that assumption false. The 137-year-old specimens belong to a newly named genus called Frankixalus, and have been renamed Frankixalus jerdonii.

The research team discovered members of the new genus living in the forests of northeast India. But they believe the genus may be spread across a large swath of Southeast Asia, as well as China.

The new genus is described in a paper published in the journal PLOS ONE.

Part of the reason the frogs proved so elusive is that they live in tree holes roughly 20 feet above the ground. They boast a variety of peculiar habits. Mothers lay eggs on the sides of the tree holes. When the eggs hatch, the tadpoles tumble into pools of water collecting in the bottom of the holes. The mothers then feed unfertilized eggs to their young, while adults supplement their diets with vegetation -- both rarities among amphibians.

Though the new genus appears to be surprisingly abundant, Biju says amphibians occupying niche forest habitat are always under threat, especially with the high rate of deforestation in India and Southeast Asia.

"Since the new genus shows remarkable parental care behavior with specific microhabitat requirements for their survival, populations discovered from highly disturbed forests are already facing extinction threats," Biju said in a press release.

The frogs' discovery is exciting but maybe not all that surprising. The forests and foothills of the Himalayas continue to yield a variety of secrets to curious and patient scientists. More than 200 new species have been discovered there since 2009.

"This part of southeast Asia, in particular, is poorly inventoried," James Hanken, curator of herpetology at Harvard University's Museum of Comparative Zoology, told National Geographic.

"I wouldn't be at all surprised if additional species were discovered."