Discovered: First Lungless Frog

Peter Herbolzheimer Rhythm Combination & Brass: Frog Dance
Wide Open (MPS, 1973)

For the full article: Live Science l Playahata

The enigmatic amphibian, dubbed Barbourula kalimantanensis, apparently gets all the oxygen it needs through its skin.

Scientists first saw one of these frogs 30 years ago, but due to their rarity, just one other specimen had been collected since then and neither had been dissected.

"No one thought to open them up — there was no real reason to believe that they could be lungless," said researcher David Bickford, an evolutionary biologist at the National University of Singapore. "Because these specimens were so rare, they had never been dissected. If you have just one specimen in your museum, you don't want to rip it open!"

Other organ weirdness

It appears that the rest of the internal organs in these frogs have shifted position to take up the space once filled by the lungs. "So we had the stomach, spleen and the liver up in the area where lungs are normally found," Bickford said. "Interestingly, we also discovered some abnormal cartilage around the area where the lungs should have been that we are still investigating."

The loss of lungs helped the frogs severely flatten their bodies. This in turn increased the surface area of their skin, which helps them absorb oxygen.

The researchers conjecture the loss of lungs might be an adaptation to the cold, fast rivers the frogs live in. Such waters naturally have high oxygen content. Also, the frogs would rather sink than float and get carried away in the water, so getting rid of lungs, which behave as flotation devices, would prove helpful.

Amphibians are also cold-blooded, "so their inherent energy requirements are very small — roughly 10 percent that of a similar sized mammal," Bickford said. "If you don't need as much oxygen anyhow, it might be easier to change, to lose lungs as the primary respiration organ."