Remains of giant frog discovered in Madagascar

A team of researchers, led by Stony Brook University palaeontologist David Krause, Ph.D., has discovered in Madagascar the remains of what may be the largest frog ever to exist. Moreover, the 16-inch, 10-pound ancient frog, scientifically named Beelzebufo, or devil frog, links a group of frogs that lived 65 to 70 million years ago to some types living today in South America.

'Beelzebufo appears to be a very close relative of a group of South American frogs known as 'ceratophyrines,' or 'pac-man' frogs because of their immense mouths,' said Dr Krause, Distinguished Service Professor in the Department of Anatomical Sciences at Stony Brook University. 'But Beelzebufo was much larger than any of its relatives or any other living frog, as if it was on steroids.'

The largest living frog is the goliath frog of West Africa, which attains lengths of 12.5 inches and weights of 7.2 pounds. The largest frog on Madagascar today, at just over four inches long, 'would have been a nice hors d'oeuvre for Beelzebufo,' Dr Krause said.

Discovery of the voracious predatory fossil frog - reported in this week's online issue of the Proceedings of the National Academy of Sciences - is significant in that it may provide direct evidence of a one-time land connection between Madagascar, the largest island off Africa's south-east coast, and South America that did not involve Africa. Dr Krause's collaborators were fossil frog experts Susan E. Evans, Ph.D., lead author of the PNAS article, and Marc E. H. Jones, Ph.D., of the Research Department of Cell and Developmental Biology at University College London in England.

'The finding presents a real puzzle biogeographically, particularly because of the poor fossil record of frogs on southern continents,' said Dr Krause. 'We're asking ourselves, 'What's a 'South American' frog doing half-way around the world, in Madagascar?''

He said that because frogs 'are not adept at dispersal across marine barriers, and since the few fossil frogs that are known from the Late Cretaceous of Africa are unrelated to Beelzebufo, one distinct possibility is that there was a sort of land connection between South America and Madagascar during that period.'

Dr Krause explained that some geoscientists have recently suggested a lingering physical link between South America and Madagascar during the Late Cretaceous Period through Antarctica. Antarctica in the Late Cretaceous was much warmer than it is today. Dr Krause and his colleagues have hypothesised this connection based on previous discoveries of sauropod and theropod dinosaurs, crocodiles, and mammals in Madagascar that were very closely related to forms in South America.

To identify Beelzebufo, and determine its relationship to other frogs, Dr Krause collaborated with Drs Evans and Jones of University College London. Together, the researchers summarised their findings in their article, 'A giant frog with South American affinities from the Late Cretaceous of Madagascar.' The authors concluded that the new frog represents the first known occurrence of a fossil group in Madagascar that has living representatives in South America.

As a result of the team's phylogenetic analysis of Beelzebufo, a scientific process elucidating the evolutionary relatedness of organisms, they determined that the fossil belongs to a group of living frogs, the 'ceratophryines,' known to camouflage themselves in their surroundings and to be ambush predators. Some of its living relatives (i.e. Ceratophrys) have horns on their heads.

Since the discovery of the first bones found in north-western Madagascar in 1993, Dr Krause and his team have gathered approximately 75 specimens of fossil fragments of Beelzebufo. Through the accumulation of these fossil finds, the team has been able to reconstruct the beast's skeleton, including almost the entire skull. Not only was the frog huge, it was powerful in design, had a protective shield, an extremely wide mouth and powerful jaws. These features made Beelzebufo capable of killing lizards and other small vertebrates, perhaps even hatchling dinosaurs.

According to Dr Krause, Beelzebufo is certainly one of the largest frogs found on record and was perhaps the largest frog ever to exist. The size and robustness of its bones and its relatedness to the rotund South American forms indicates it was probably the heaviest frog ever. The mammoth size, girth, appearance, and predatory nature of the frog prompted its discoverers to call it the 'armoured frog from hell.' They derived the genus name from the Greek word for devil (Beelzebub) and the Latin word for toad (bufo). The species name, dubbed 'ampinga,' means 'shield.'

As part of his long-term research program, Dr Krause intends to continue to launch expeditions to collect specimens of Beelzebufo and other ancient animals in Madagascar. The research is funded by the National Science Foundation and the National Geographic Society.