Discovery Changes View of Ancient Origins of Lungless Frogs
The rare Philippine flat-headed frog, Barbourula busuangensis
What do the highly celebrated Bornean lungless frogs and the rare Philippine flat-headed frogs have in common? The answer, scientists revealed this week, is tens of million years of evolutionary history and potential isolation of their ancestors on a small “raft” of islands that split from mainland Asia 30 million years ago.
The surprising findings, the result of collaboration between scientists in four countries, were announced today in the international journal PLoS ONE. Dr. David Blackburn, KU Biodiversity Institute researcher and the lead author on the findings, said that the results "reveal a very ancient origin to these enigmatic frogs and suggest a new interpretation for the origins and history of some animal species inhabiting the western islands of Philippines.”
“If our results are correct,” said scientist Arvin Diesmos, co-author on today’s paper and a curator at the National Museum of the Philippines in Manila, “the ancestors of lungless frogs may have become isolated on a small chain of islands that rifted from the Asian mainland 30 million years ago. These highly distinctive, threatened frogs may have acquired their unique characteristics during the period that they were isolated on the Palawan raft.”
The subject of the new study is the evolutionary origins of the lungless and flat-headed frogs, known to scientists as Barbourula kalimantanensis (from south-central Borneo Island) and Barbourula busuangensis (from Palawan Island in the western Philippines). The study involved scientists from the University of Kansas, the National Museum of the Philippines, the National University of Singapore, and the Bandung Institute of Technology, Indonesia. The team sequenced a large number of genes and performed molecular clock analyses to date the evolutionary origins of lungless and flat-headed frogs.
“Our findings have the potential to turn the “Palawan Paradigm” on its head, stated Rafe Brown, KU curator of herpetology and recipient of the National Science Foundation grant that funded the research. “Given our new data, we must consider the possibility that these unique amphibians survived 20 million years in the Philippines before dispersing to Borneo—and not the other way around.”
Brown also emphasized several other recent studies which, together with the new findings, emphasize the evolutionary uniqueness of the western Philippines and reject the past 150 years’ prevailing interpretation of the western Philippines as simple, unremarkable “faunal peninsula” of Borneo.