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Scientists report discovery of lungless frog in Borneo that breathes through its skin

A lungless frog nicknamed ‘Barbie’ is pictured in this photo provided by evolutionary biologist David Bickford yesterday. PHOTO: EPA

A rare and primitive frog living in a remote Borneo stream has no lungs and apparently absorbs oxygen through its skin, researchers reported on Wednesday.

The aquatic frog has evolved backwards, reacquiring a primordial trait, David Bickford of the National University of Singapore and colleagues reported.

Studying the frog could help shed light on how lungs evolved in the first place, they wrote in the journal Current Biology.

They also said that illegal gold mining in the area may threaten the unique species.

“The evolution of lunglessness in tetrapods [amphibians, reptiles, birds and mammals] is exceedingly rare, previously known only from amphibians — two families of salamanders and a single species of caecilian [blindworm],” they wrote.

“Here we report the first case of complete lunglessness in a frog, Barbourula kalimantanensis, from the Indonesian portion of Borneo,” they wrote.

The frog, nicknamed “Barbie” — short for its scientific name — may be endangered because of mining activity, the researchers said.

“In August 2007, we visited ... near NangaPinoh, Western Kalimantan, but found that illegal gold mining had destroyed all suitable habitats in the vicinity,” they wrote.

They snorkeled, waded and turned over boulders to find their quarry.

“The originally cool, clear, fast-flowing rivers are now warm and turbid. Water quality around the ... locality is no longer suitable for the species, but we were able to rediscover two new populations upstream,” they said.

“We knew that we would have to be very lucky just to find the frog,” Bickford said in a statement.

Animals evolved lungs when they moved from the sea to land millions of years ago.

Animals have only lost this important adaptation a few times, Bickford’s team said.

“The discovery of lunglessness in a secretive Bornean frog, supports the idea that lungs are a malleable trait in the Amphibia, the sister group of all living tetrapods,” the researchers wrote. “Amphibians maybe more prone to lunglessness since they readily utilize other methods for gas exchange.”

“This is an endangered frog that we know practically nothing about, with an amazing ability to breathe entirely through its skin, whose future is being destroyed by illegal gold mining by people who are marginalized and have no other means of supporting themselves,” Bickford said in an interview.

Only animals with small body sizes, slow metabolisms and living in fast-flowing cold water where oxygen and carbon dioxide are exchanged quickly may be able to survive without lungs, the researchers said.

Bickford said that he hoped the find would spur more research into Southeast Asian wildlife, much of which is threatened by development and other losses of habitat.

“The discovery is not so much a surprise to the scientific community, as much as a surprise that it has taken so long to find it,” Bickford was quoted as saying in a report in the Strait Times.

“We strongly encourage conservation of remaining habitats of this species,” the researchers said.
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