An article describing a “lungless” frog species residing in Borneo was retracted at the request of the lead author earlier this month in light of new data. Using traditional dissection and histology techniques, Dr. David Bickford (who worked at the National University of Singapore at the time) and colleagues had described the apparent lack of lungs in Barbourula kalimantanensis frogs, which would place this species among only a few known amphibia (salamanders and one species of caecilian) without lungs and would have been the only species of frog in the list. Living in an aquatic environment, it was hypothesized that the species lost their lungs over time because they were not necessary as oxygen could be obtained from the surrounding water through skin respiration. Moreover, the authors reasoned that their aquatic environment had strong currents, which may have made it difficult for the frogs to stay put if they had lungs that would make them buoyant.
Using new high-resolution micro-CT scanning technology, however, a new team of researchers at the Florida Museum of Natural History (University of Florida) led by Dr. David Blackburn, re-examined the original frog specimens. They took a closer look at a hole they observed at the bottom of the mouth where they discovered a small glottis, a short trachea, and a tiny pair of thin-walled lungs. The relatively small respiratory system compared to other species of frogs suggests that it may indeed play a minor role in gas exchange as compared to the skin, and may help protect buoyancy, as originally hypothesized by Dr. Bickford. Dr. Blackburn and colleagues further hypothesized that the smaller lungs may help with transmitting low frequency sounds.
Sources:
Retracted: Bickford D, Iskandar D, Barlian A. A lungless frog discovered on Borneo. Current Biology. 18(9): R374, 2008.
Blackburn DC, Gray JA, Stanley EL. The only “lungless” frog has a glottis and lungs. Current Biology. 34(10): R492-R493, 2024.
Categories: Extreme Animals, Nature's Solutions
Tags: frog, lungless, lungs, respiration
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