Weird Lungless Frog

Bizarre Frog Has No Lungs, By Charles Q. Choi, Special to LiveScience, posted: 07 April 2008 ET


The first lungless frog has been discovered lurking in the jungles of Borneo.
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!"

The amphibians, no more than 2 inches long, have proven elusive because they live in cold, fast rivers in remote areas of the rainforests of Kalimantan, the Indonesian part of Borneo. Also, they are slippery "and can be surprisingly fast for short bursts," Bickford said. "We had a team of 11 people looking for these frogs and it took us almost two weeks before we found any."
He and his colleagues had no idea this frog would be lungless.

"I was just going to be happy if we simply rediscovered the frogs," Bickford said. "It had been 30 years of intermittent searching for this frog until we could put together a multinational team and get to the last remaining areas where it could realistically be found."

As Bickford and his colleagues went snorkeling in the rivers where the frogs live, the water proved so cold that "after just 45 minutes of snorkeling, I would have to stop because I was shaking uncontrollably, my lips were blue, and my breathing became too labored to actually snorkel effectively," Bickford told LiveScience. "This is lowland rain forest in Borneo, just off the equator, and I had hypothermia! That certainly was something I was not entirely prepared for."
"There are so many difficulties in field work, and yet it remains my biggest joy," Bickford added. "Having the undeniable privilege of going out to these remote sites, seeing some of the last and greatest treasures that exist in the wild, and then getting to study them — well, every day I feel lucky."

As the researchers were doing initial dissections of the frogs as they caught them in the field, they were surprised to discover these amphibians lacked lungs. "At first I did not believe that the frogs had no lungs, but then, we just kept on seeing the evidence pile up. I was flabbergasted," Bickford said.

"The thing that struck me most then and now is that there are still major firsts — for example, first lungless frog! — to be found out in the field," Bickford added. "All you have to do is go a little ways beyond what people have done before, and — voila!"

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."
More lungless animals

The family of frogs this novel amphibian belongs to ranks among one of the most primitive, if not the most primitive. The more primitive lineages could have an easier time switching to lunglessness, but "at this stage this is all conjecture," Bickford said.

The loss of lungs has been known to occur two other times in all the creatures with backbones that have waddled onto land across geologic time. Each time this loss has happened in amphibians — in a species of caecilian, a limbless beast resembling an earthworm, and in many species of salamanders. How and why this change evolved in these animals has been long debated, and the new frog could shed light on this curious phenomenon.

The closest relative of this frog, which dwells in the Philippines, has lungs.

"We don't even know what they eat, although we have some good guesses from two full stomachs," Bickford said. "How do they locate and attract mates? What do their eggs look like? Do they even lay eggs, or do they have a more derived mode of reproduction where the eggs directly develop into small frogs? Do they have tadpoles? What are their habitat requirements? How many are left?"

The rarity of this frog could hamper further studies into it, Bickford added. The amphibian could become even more rare, given the increasing damage to its environment as the result of toxic metals used in mining and other unfortunate consequences of development on the island.
"The once cool and clear streams have mostly turned murky and warm, contaminated with human pollutants, run-off from agriculture and mercury from the gold mining," Bickford said. "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. There are no simple answers to this problem."

One of the primary goals of the researchers now is to garner more support for conserving the last remaining wild spots in Borneo, "and I think we have a flagship species in these lungless frogs," Bickford said. "There is so much we do not understand about nature and at least part of the reason to protect it is to protect our own futures."

Bickford and his colleagues Djoko Iskandar and Anggraini Barlian will detail their findings in the journal Current Biology.

Beelzebufo: Largest Known Frog

Here comes Beelzebufo! The Devil Toad. A Frog the Size of a Bowling Ball.

Here' s the story.
February 18, 2008A team of researchers, led by Stony Brook University paleontologist David Krause, has discovered the remains in Madagascar of what may be the largest frog ever to exist. 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 with frogs living today in South America. Discovery of the voracious predatory fossil frog -- reported on-line this week in the journal Proceedings of the National Academy of Sciences (PNAS) -- is significant in that it may provide direct evidence of a one-time land connection between Madagascar, the largest island off Africa's southeast coast, and South America.

To identify Beelzebufo and determine its relationship to other frogs, Krause collaborated with fossil frog experts Susan Evans, lead author of the PNAS article, and Marc Jones of the University College London. The authors concluded that the new frog represents the first known occurrence of a fossil group in Madagascar with living representatives 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 Krause, whose research was funded by the National Science Foundation (NSF). The ceratophryines are known to camouflage themselves in their surroundings, then ambush predators.

"The finding presents a real puzzle biogeographically, particularly because of the poor fossil record of frogs on southern continents," said 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 in Africa are unrelated to Beelzebufo, one possibility is that there was a land connection between South America and Madagascar during that period."

Some geoscientists have suggested a lingering physical link between South America and Madagascar during the Late Cretaceous Period -- a link involving Antarctica. Antarctica in the Late Cretaceous was much warmer than it is today. "The occurrence of this frog in Madagascar and its relatives' existence in South America provides strong evidence that the supercontinent Gondwana 'disassembled' during the latest part of the Cretaceous," said Richard Lane, program director in NSF's Division of Earth Sciences.

Krause and colleagues have hypothesized 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. Beelzebufo is one of the largest frogs 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 also probably the heaviest frog to exist.

The size, girth, appearance, and predatory nature of the frog prompted its discoverers to call it the "armored 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, ampinga, means "shield."The largest living frog today is the goliath frog of West Africa, which attains lengths of 12.5 inches and weights of 7.2 pounds. The largest frog alive on Madagascar today, at just over four inches long, "would have been a nice hors d'oeuvre for Beelzebufo," Krause said.

Since the discovery of the first bones found in northwestern Madagascar in 1993, Krause and his team have gathered some 75 fossil fragments of Beelzebufo. Through the accumulation of these fossils, the team has been able to reconstruct the frog's skeleton, including nearly 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.

The research was also funded by the National Geographic Society.

Weird Suriname Frog

This remarkable-looking toad may be a new species to science. It belongs to the genus Atelopus, and was discovered during a survey of the Nassau plateau in mid-2006 by Surinamese scientists Paul Ouboter and Jan Mol.

June 4, 2007

PARAMARIBO, Suriname - A toad with fluorescent purple markings and 12 kinds of dung beetles were among two dozen new species discovered in the remote plateaus of eastern Suriname

The expedition was sponsored by two mining companies hoping to excavate the area for bauxite, the raw material used to make aluminum, and it was unknown how the findings would affect their plans.

Scientists discovered the species during a 2005 expedition led by the U.S.-based nonprofit Conservation International in rainforests and swamps about 80 miles (128 kilometers) southeast of Paramaribo, the capital of the South American country, organization spokesman Tom Cohen said.

25 million year old frog

Researchers believe that this frog recently found in Mexico could have been preserved in amber for 25 million years.jpg

Paa Frog from Mt Everest

A Paa frog, photographed in Nepal.

Hypersonic Frog

A small frog species from China is the first amphibian shown to use ultrasonic calls. The male concave-eared torrent frog can hear extraordinarily high frequencies with its unusual, recessed ear (arrow and inset), an advantage for life in a noisy place. Equipment designed for studying bats picked up high-pitched chirrups in the calls of the concave-eared torrent frog Amolops tormotus, says Albert S. Feng of the University of Illinois at Urbana-Champaign. He and his colleagues also measured nerve activity in the hearing centers of the frog brains in response to ultrasonic tones.

The small brown frogs live beside water splashing over rocks on a mountainside in Huangshan Hot Springs, China. Ultrasonic perception may have developed as the frogs struggled to hear each other over the din, the researchers suggest in the March 16 Nature.

High-pitched signaling is "absolutely unexpected," says Michael Ryan of the University of Texas at Austin, who studies frogs and frog-eating bats.