AMPHIBIANS IN SOUTHEAST ASIA
Jodi Rowley, herpetologist with the Australian Museum in Sydney, told mongabay.com: “Southeast Asian amphibians are poorly known—new species are continuously being discovered and for the species that we do know of, we don’t know enough about many of them to know if they're threatened with extinction or not. In fact, 36 percent are so poorly known that they are listed as "Data Deficient" according to the global IUCN Red List, which is 11 percent higher than the global average for amphibians. Because we don’t yet know the true diversity or conservation status of Southeast Asian amphibians, they've tended to slip under the global conservation radar. However, the fact we don’t know enough about what is going on is alarming in itself—there’s actually very good reasons to be concerned about Southeast Asian amphibians. [Source: Jeremy Hance, mongabay.com, February 6, 2012 ::::]
“Even as amphibians face unprecedented challenges—habitat loss, pollution, overharvesting, climate change, and a lethal disease called chytridiomycosis that has pushed a number of species to extinction—new amphibians are still being uncovered at surprising rates. One of the major hotspots for finding new amphibians is the dwindling tropical forests of Southeast Asia. The best place to discover new amphibian species in Southeast Asia are high-altitude montane forests. Rowley says there is a number of reasons for this: "Montane forests are areas of high amphibian diversity. They’re also areas of high endemism—over time, frogs on mountains often become 'trapped,' unable to cross valleys to reach the next mountain, and become different species—those adapted to the unusually cool, wet conditions found at the top of mountains. The inaccessibility of montane areas (rugged terrain in remote areas) has also afforded the forest in these areas some protection from habitat destruction." ::::
“A large proportion of the amphibians in Southeast Asia remain undiscovered. Exactly how many, I’m not sure. Looking at how many new species of amphibian are described from Southeast Asia every year, there’s still a lot to discover. I have a few favorite places, and each of these places are special for different reasons. Because it's the place that I have been back to the most, I do love the Langbian Plateau in southern Vietnam. The amphibians of the area are diverse, and many are known only from the Plateau's misty mountains. I’ve also worked with protected areas staff in the area for many years, and so got to know them well. ::::
“With the paucity of knowledge on Southeast Asia's amphibians, scientists know less about their overall conservation status as compared to amphibians in Africa and Latin America. However, given that Conservation International has dubbed Southeast Asia's tropical forests the most imperiled in the world, it's likely that many of the region's amphibians are struggling to survive.” ::::
Vampire and Bird Frogs of Southeast Asia
Jodi Rowley told mongabay.com:“So far, my colleagues and I have discovered and described ten species of frog. The actual discovery—spotting the frog and realizing that it’s from a species not known to science—is fantastic, but brief. Most of the work actually occurs once we are back in the lab—comparing the body size and shape, and colors and patterns on the frog to other species known from the region, and examining molecular data and advertisement call recordings. [Source: Jeremy Hance, mongabay.com, February 6, 2012 ::::]
“I have a particular fondness for the vampire flying frog (Rhacophorus vampyrus). It’s also been the species that has received the most attention. Its unusual name is for a good reason though—the tadpoles of the species are truly bizarre. With two, curved, black "fangs" protruding from their mouth in place of the usual tadpole mouthparts, I think it deserves the name and the attention! There’s no doubt a fascinating reason for these teeth—and we’re working on discovering that. The frog itself is also quite a beautiful species—brick red, black and white, with large, golden eyes. ::::
“Quang’s tree frog is unique in its tiny size, turquoise skin and black and yellow patterns, but it’s most unusual because of its call. Instead of calling repeatedly "croak, croak, croak..." as most frogs tend to do, males of this species make an unpredictable and variable array of clicks and whistles. No two of calls are the same—making it a little more like a bird than a frog in terms of calls. “ ::::
The Bornean horned frog is brown and black and very well camouflaged, blending in perfectly with the leaf litter where it hangs out. They are very hard to find. They don’t move now matter how close one approaches. In terms of prey, it simply waits for insects and other small creatures to pass its way.
Threatened Amphibians in Southeast Asia
Jodi Rowley told mongabay.com: “Southeast Asian amphibians are facing some serious threats—including the highest deforestation rates on the planet and overharvesting (for food, pets or traditional medicine). They’re also now known to be infected by the pathogen responsible for amphibian declines and extirpations globally (Batrachochytrium dendrobatidis). So by all accounts, they are facing a very real extinction crisis. However, because we know so little about the amphibians of the region, and haven’t been monitoring populations all over the region, amphibian population declines and extinctions may be going unnoticed. ::::
“By far the greatest threat to amphibians in Southeast Asia is habitat loss. While some amphibians are able to persist in human-modified habitats such as pastures, rice-paddies and even cities, most simply can’t tolerate much habitat modification at all. For example, many amphibians are almost completely arboreal, even breeding in water-filled pools in trees. Without a healthy forest with lots of "holey" trees, there’s no way they can survive. ::::
“Amphibians are harvested for food (either to feed people or animals), for use as traditional medicine, and for the domestic and international pet trade. Harvesting amphibians for food is on a much greater scale than the other two, and there’s evidence that over-harvesting for human consumption may be threatening long-lived and large-bodied frogs—they seem to be absent in areas where they were once abundant. The harvesting and trade of Southeast Asian salamanders is also very worrying. Salamanders in the region are used as traditional medicine and are in high demand in the international pet trade. Because very high prices are commanded for each individual (up to several hundred U.S. dollars), particularly if they belong to a rare species, there’s incentive to catch every last one. ::::
On the the fungal disease, chytridiomycosis, which has decimated amphibian populations in the Americas, Rowley said : We know that the pathogen responsible for the disease, Batrachochytrium dendrobatidis, is present and infecting amphibians in Southeast Asia, but we don’t know if it’s actually causing disease (eg. making the frogs sick) or affecting the populations of amphibians in the region. So far, there's no evidence that it is, but a lot more research is needed to determine if this is the case. If it is causing population declines as it has in other parts of the world, then the disease could quickly become the greatest threat facing amphibians in Southeast Asia—potentially wiping out the amphibian species that have been spared from habitat loss. We're currently hoping that Southeast Asian amphibians are somehow resistant.
According to an article published in the journal Conservation Biology last October, the wild harvesting of amphibians and reptiles is driven chiefly by consumer demand, largely from developed nations but increasingly, from Asian countries. At the losing end of the bargain are South-East Asian countries, the source of these wildlife. We’ve already encountered the “Asian Turtle Crisis” which saw drastic declines in tortoises and freshwater turtles in the region. Now, it looks like the trade in Asian snakes is fast gearing up to become another crisis.
Scientists Find a Frog with a Mushroom Growing on its Back
In June 2023, Indian scientists on a nature walk through the foothills of the Western Ghats came across a living frog that seemed to have a mushroom sprouting from its back. Eric Lagatta wrote in USA TODAY: The group of five came across a small roadside pond packed with about 40 tiny frogs, they noticed something odd about one of them. Perched on a twig, the frog had a bizarre growth on its left flank that, upon closer examination, was clearly a small gray mushroom. Hobbyist naturalist Chinmay Maliye and Lohit Y.T., a river and wetlands specialist at World Wildlife Fund-India, were quick to photograph the discovery before the group continued onward. “To the best of our knowledge, never has a mushroom sprouting from the flank of a live frog been documented,” the team wrote in a report in January documenting the finding in the journal Reptiles and Amphibians. [Source: Eric Lagatta, USA TODAY, February 15, 2024]
The frog was among dozens of Rao’s Intermediate Golden-backed frogs (Hylarana intermedia) packing the pond. The frogs, which are about the size of a human thumb, are native to the region and are found in abundance in the Western Ghats, the authors wrote. Lohit posted the close-up images of the frog online in the nature journal to see if any citizen scientists could identify the fungal growth.
Mushroom enthusiasts and experts alike jumped in to suggest it could be a bonnet mushroom in the genus Mycena. This type of mushroom primarily thrives on decaying organic matter like plants and rotting wood, which is why experts were baffled about why one was seemingly growing on a living frog.
Although plenty of fungi grow on living things, including the yeast that grows on our skin, most don't become mushrooms. For a mushroom to grow, a fungal spore has to find a viable home on some sort of surface before it can produce mycelia, similar to a plant's root. The mycelia produces a mushroom only if it finds enough nutrients to grow.
Fanged Frog Produces Live Tadpoles Rather Than Eggs
(b) Female with tadpoles removed from the oviduct.
(c) Adult male calling by a stream; two tadpoles visible within the circle;
(d) dorsal and ventral views of tadpoles released by a female at the moment of capture
In December 2104, scientists announced in a study published in the journal Plos One that they had discovered a new species of amphibian — a fanged frog — discovered on Sulawesi Island in Indonesia that gave birth to live tadpoles. Most frogs lay eggs and although some species give birth to froglets, newborn tadpoles are new to science. Zoologists had chased the frog for decades because they suspected there was something unique about it. [Source: Jonathan Webb, BBC News, December 31, 2014]
The BBC reported: “Dr Jim McGuire from the University of California, Berkeley, actually thought he was holding a male frog the first time he witnessed a birth. In fact, he had in his hands a pregnant female and, suddenly, a clutch of brand new tadpoles, which were about 1.5 centimeters long, appeared. The scientists called the new species Limnonectes larvaepartus. The Limnonectes family are known as fanged frogs because of twin projections on their lower jaws that are used in fighting.
“Nearly all the world's 6,000 frog species use external fertilisation: the female lays eggs during mating, while the male releases sperm to fertilise them. “"But there are lots of weird modifications to this standard mode of mating," Dr McGuire said. "This new frog is one of only 10 or 12 species that has evolved internal fertilization, and of those, it is the only one that gives birth to tadpoles, as opposed to froglets or laying fertilized eggs."
“How the male frogs manage to fertilise eggs inside the female remains a mystery, because frogs have no conventional sexual organs to transfer the sperm. Two species found in California have evolved a penis-like "tail" that does the job, but the scientists found no such contrivance on the new Indonesian species.
“Prof Djoko Iskandar, a collaborator of Dr McGuire's from the Bandung Institute of Technology in Indonesia, first spotted this new type of fanged frog in the 1990s but they had not been confirmed as a distinct species until now. Ben Tapley, team leader of herpetology at the Zoological Society of London (ZSL), said the new finding was "totally out of the blue". "They're relatively dull frogs, actually," Mr Tapley told BBC News. "To find out something totally surprising about a frog you would barely notice in the forest is really cool...Finding a new species is not that rare — but actually discovering a new reproductive mode is," Mr Tapley said.
“There are thought to be up to 25 species of Limnonectes frogs on Sulawesi, but only four have been described so far — including the new larvaepartus. Little is known about any of the animals' biology. "There are more than 40 of these modes in amphibians, but this one is obviously totally unique," Tapley said. “He added that the region where the frog was discovered has one of the highest deforestation rates in the world. "These kind of findings are really valuable, especially in Sulawesi where most of the forest is gone. "It's great that we're learning about these species before it's too late."
Flying Frogs in Borneo
Flying frogs in Borneo use exaggerated webbed feet and lose flaps of skin on their limbs to glide from tree to tree and descend to breeding sites. They have adhesive pads on the bottom of their feet, which allows them land on the sides of trees. The harlequin tree frog is such an expert flyer it can make 180 degree bank turns. The flying frog lays its eggs on branch above pools of water. When the eggs hatch the tadpoles drop into the water.
The largest of Borneo’s flying frogs, the jade tree frog, was discovered in the 19th century by the famous naturalist Alfred Russel Wallace. It is little studied by scientists and has never been observed gliding. They spend most of their time in the upper canopy and rarely descend except to breed. These frogs have transparent skins. Before the female lays her eggs you can see them through her skin.
Describing a flying Borneo frog, David Attenborough wrote, "It has webbed toes so elongated that when it launches itself into the air, each foot acts as a parachute...so that when the frog leaps it can glide considerable distances from one tree to another.”
Pea-Sized Frog Found in Borneo
In April 2010, Associated Press reported: “One of the world's tiniest frogs — barely larger than a pea — has been found living in and around carnivorous plants in Borneo, one of the scientists who made the accidental discovery said. Indraneil Das, a scientist at University Malaysia Sarawak, and another scientist from Germany were researching frogs in Malaysia's Sarawak state on Borneo island when they chanced upon the tiny species on a mountain road in the Kubah National Park in 2006. "For biologists, this is a curiosity," Das told Associated Press. [Source: Associated Press, August 26, 2010]
Adult males of the amphibians range in size between 10.6mm and 12.8mm, said Das. The frogs were named Microhyla nepenthicola after the pitcher plant species where they live. A Malaysian museum had listed the species but misidentified it as a juvenile of another frog species, he said. The tubular plants are carnivorous, killing insects such as ants, but do not harm the frogs. Tadpoles grow in the liquid inside the plants. The findings were published (pdf) by Das and Alexander Haas of the Biozentrum Grindel und Zoologisches Museum of Hamburg, Germany in the journal Zootaxa last week.
Because the frogs were so small, Das and his colleague only found them by tracking their singing of "harsh rasping notes" at dusk. They caught them by making them jump on a white cloth near the pitcher plants. The discovery should encourage efforts to protect the biological diversity in Borneo's rainforests. Das said the tiniest known frog — at 9.8mm — found was in Cuba. A 8.5-millimeter frog species found in southern Papua new Guinea was named not only the world’s small frog, but the world’s smallest vertabrate, in 2012.
Captive Frogs May Be Spreading Diseases to Wild Frogs in Southeast Asia
Jeremy Hance of mongabay.com wrote: “Scientists have documented a series of links between exotic frogs for trade and diseases in wild frogs in Southeast Asia, including the first documented case of the chytrid fungus—a virulent and lethal disease—in Singapore. According to researchers writing in a new study in EcoHealth, frogs imported into Southeast Asia as pets, food, or traditional medicine are very likely spreading diseases to wild populations. [Source: Jeremy Hance, mongabay.com, March 07, 2013]
Collecting samples of some 2,300 wild and captive frogs across four countries (Laos, Cambodia, Vietnam, and Singapore), researchers found that disease was widespread. Most worryingly, the researchers found chytrid fungus on two wild frogs and eleven captive frogs in Sinapore. In fact, four out of seven pet stores visited on the island nations sold frogs already infected with chytrid. They believe the American bullfrog is the primarily culprit."Since the American bullfrog is able to tolerate this pathogen, it may act as a carrier for spreading chytrid to the region when it is imported through commercial trade," explains lead author Martin Gilbert with the Wildlife Conservation Society (WCS).
Chytrid fungus has spread rapidly around the world, decimating even remote and protected frog populations. It is believed to be responsible, at least in part, for a number of extinctions worldwide. Fortunately the team didn't detect chytrid fungus in Laos or Vietnam, but did find one imported frog—to be sold as food—that was carrying the disease. Another worrisome disease, ranavirus, was not discovered during testing. However, the researchers also report that amphibians in Vietnamese frog farms were rife with skin lesions. Every frog tested—497 individuals—at 23 different facilities sported some type of skin disease from inflammation to missing digits.
"In light of the fact that this emerging infectious disease is now known to be spread by commercial trade, it is in everyone’s best interest to eliminate it from the trade in live animals before both the native amphibian populations of Southeast Asia are affected and before it completely decimates the commercial trade and people are unable to make a living," said co-author David Bickford with the NUS Faculty of Science, adding, "This is not just about the frogs."
Image Sources: Wikimedia Commons
Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, CNN, BBC, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.
Last updated February 2025