Posts Tagged ‘Amphibians’

New Findings On Immune System In Amphibians May Assist Conservation Efforts

June 19, 2008

Major Histocompatibility Complex (MHC) genes produce proteins that are crucial in fighting pathogen assault. Researchers from the Jagiellonian University in Krakow and from the Helmholtz Centre for Environmental Research (UFZ) characterized genetic variation and detected more than one MHC class II locus in a tailed amphibian. Unlike mammals, not much has been known until now about the immune defence of amphibians.

Globally, amphibian populations are in an unprecedented decline, to a considerable extent caused by rapidly spreading infectious diseases, such as the fungal infection Chytridiomycosis. Therefore future conservation strategies for amphibians could benefit from knowledge about species-specific adaptations indicated by MHC variation, say the researchers writing in the journal Molecular Ecology.

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Large Areas Of Conservation Land Needed To Save Small Frogs, Turtles And Other Marine Species

June 12, 2008

Scientists were surprised with findings of a recent study that reveals many animal species believed to persist in small contained areas actually need broad, landscape level conservation to survive.

With more species at risk of extinction today than any other time in human history, the findings of the study published in the debut issue of Conservation Letters provides new insight into how to improve protection for many species worldwide. Scientists from organizations including Conservation International (CI) and BirdLife International identified appropriate scales of conservation efforts for 4,239 species of mammals, birds, reptiles, and amphibians included on the IUCN Red List of Threatened Species.

“The biggest surprise was the frogs,” said Claude Gascon, executive vice president for programs and science at CI, and co-chair of the IUCN Amphibian Specialist Group. “Amphibians are small animals, and many have tiny ranges restricted to a single forest or a mountain stream. But astonishingly many species – like the Critically Endangered Lake Titicaca Giant Frog (Telmatobius culeus) from Peru – are greatly impacted by ecological processes at the landscape scale.”

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Memory In Honeybees: What The Right And Left Antenna Tell The Left And Right Brain

June 8, 2008

It is widely known that the right and left hemispheres of the brain perform different tasks. Lesions to the left hemisphere typically bring impairments in language production and comprehension, while lesions to the right hemisphere give rise to deficits in the visual-spatial perception, such as the inability to recognize familiar faces.

In the last few years, we have become used to the idea that functional asymmetry between the left and right sides of the nervous system is not unique to humans: fishes, amphibians, birds and mammals have functional and anatomical asymmetries.

So, the idea that all vertebrate species, even non-human ones without any linguistic skills, have an asymmetric brain seems to be finally accepted. Now, this process of extension among species is going on and brain lateralization has been extended beyond the class Vertebrata. Insects, with their nervous system so different from that of vertebrates, are also “lateralized”, as shown in a paper published in PLoS ONE by Lesley J. Rogers of the Centre for Neuroscience and Animal Behaviour, University of New England (Australia), and Giorgio Vallortigara, of the Centre for Mind/Brain Sciences, University of Trento (Italy).

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Toad Research Could Leapfrog To New Muscle Model

June 3, 2008

A toad sits at a pond’s edge eyeing a cricket on a blade of grass. In the blink of an eye, the toad snares the insect with its tongue. This deceptively simple, remarkably fast feeding action offers a new look at how muscles work.

This fresh perspective could lead to designing more efficient electric motors, better prostheses and new medical treatments for neuromuscular diseases like Parkinson’s.

Science has long held that muscles behave largely like motors. Northern Arizona University researcher Kiisa Nishikawa suggests that muscle acts more like a spring.

“Existing theories don’t explain how muscles shorten rapidly,” Nishikawa said. “Muscles can only shorten to do work; they can’t do work by lengthening.” A spring also can only do work by shortening.

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Reproductive Plasticity Revealed: Neotropical Treefrog Can Choose To Lay Eggs In Water Or On Land

May 23, 2008

When frogs reproduce, like all vertebrates, they either lay their eggs in water or on land — with one exception, according to new research by a team of Boston University scientists who discovered a treefrog (Dendropsophus ebraccatus) in Panama that reproduces both ways. The neotropical frog makes a behavioral decision to lay egg masses aquatically in a pond or terrestrially on the overhanging plants above a pond, where the newly-hatched tadpoles simply fall into the water.

The dual reproductive capabilities enable this species of tree frogs to choose the best environment for egg development avoiding either aquatic predators or the hot tropical sunlight that dries out the eggs. In two shady forest ponds the mating frogs laid terrestrial egg masses, as expected from previous research. In a third pond in an old gravel quarry without a forest canopy, the vast majority — 76 percent — of the eggs were laid in water, supported by aquatic vegetation. The remaining 24 percent were on leaves above the pond, although the mortality rate of these eggs was high due to the heat and lack of shade.

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Ancient Amphibian: Debate Over Origin Of Frogs And Salamanders Settled With Discovery Of Missing Link

May 22, 2008

The description of an ancient amphibian that millions of years ago swam in quiet pools and caught mayflies on the surrounding land in Texas has set to rest one of the greatest current controversies in vertebrate evolution. The discovery was made by a research team led by scientists at the University of Calgary.

The examination and detailed description of the fossil, Gerobatrachus hottoni (meaning Hotton’s elder frog), proves the previously disputed fact that some modern amphibians, frogs and salamanders evolved from one ancient amphibian group called temnospondyls.

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Female Concave-eared Frogs Draw Mates With Ultrasonic Calls

May 19, 2008

Most female frogs don’t call; most lack or have only rudimentary vocal cords. A typical female selects a mate from a chorus of males and then –silently — signals her beau. But the female concave-eared torrent frog, Odorrana tormota, has a more direct method of declaring her interest: She emits a high-pitched chirp that to the human ear sounds like that of a bird.

his is one of several unusual frog-related findings reported recently in the journal Nature.

O. tormota lives in a noisy environment on the brushy edge of streams in the Huangshan Hot Springs, in central China, where waterfalls and rushing water provide a steady din. The frog has a recessed eardrum, said Albert Feng, a professor of molecular and integrative physiology at the University of Illinois and team leader on the new study.

“In the world we know of only two species — the other one in southeast Asia — that have the concave ear,” Feng said. “The others all have eardrums on the body surface.”

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Biological Weapons To Control Cane Toad Invasion In Australia

May 12, 2008

New research on cane toads in Northern Australia has discovered a way to control the cane toad invasion using parasites and toad communication signals.

Professor Rick Shine from the University of Sydney has been studying the biology of cane toads, and will reveal his new research May 7 at the Academy of Science’s peak annual event Science at the Shine Dome.

He says that controlling toads has been difficult as things that kill them will often kill frogs. Professor Shine and his team studied cane toads in Queensland that lagged behind the invasion front and found they were infected with a lungworm parasite which slows down adults and, in laboratory tests, kills around 30% of baby toads.

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Priority Regions For Threatened Frog And Toad Conservation In Latin America

May 12, 2008

Nearly 35% of all amphibians are now threatened of extinction raising them to the position of the most endangered group of animals in the world. Decline of amphibian populations and species is ongoing due to habitat loss, fungal disease, climate shift and agrochemical contaminants. These impacts are even worse to frogs that reproduce in water bodies such as streams and ponds.

Despite of that, no study ever proposed key broad-scale regions for conserving these species till now. Rafael D. Loyola and his colleagues propose now a priority set of areas for the conservation of frogs and toads in Latin America. The study, published in this week’s PLoS ONE, is unprecedented in terms of not only the proposition of key-conservation areas, but also because it shows that the inclusion of species biological traits, such as reproductive modes, affects the performance of area-prioritization analyses.

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Legless Lizard And Tiny Woodpecker Among New Species Discovered In Brazil

April 30, 2008

Researchers discovered a legless lizard and a tiny woodpecker along with 12 other suspected new species in Brazil’s Cerrado, one of the world’s 34 biodiversity conservation hotspots.

The Cerrado’s wooded grassland once covered an area half the size of Europe, but is now being converted to cropland and ranchland at twice the rate of the neighboring Amazon rainforest, resulting in the loss of native vegetation and unique species.

An expedition comprising scientists from Conservation International (CI) and Brazilian universities found 14 species believed new to science — eight fish, three reptiles, one amphibian, one mammal, and one bird — in and around the Serra Geral do Tocantins Ecological Station, a 716,000-hectare (1,769,274-acre) protected area that is the Cerrado’s second largest.

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Road Kill Losses Add Up, Taxing Amphibians And Other Animals

April 17, 2008

When frogs hit the road, many croak. Researchers found more than 65 animal species killed along a short stretch of roads in a Midwestern county. Nearly 95 percent of the total dead were frogs and other amphibians, suggesting that road-related death, or road-kill, possibly contributes to their worldwide decline, a trend that has concerned and puzzled scientists for decades.

The Purdue University study found that habitat along roadsides heavily influences road-kill. More than 75 percent of the carcasses originated alongside a one-mile stretch of road that traverses a wildlife-friendly wetland known as Celery Bog in West Lafayette, Ind.

“On hot summer nights when it rains, there are literally thousands of frogs out there,” said Andrew DeWoody, a Purdue researcher who led the study in Tippecanoe County, home to the university.

During the 17-month study, researchers found 10,500 dead animals along 11 miles of roads. Of those, 7,600 were frogs of unidentifiable species and another 1,700 were bullfrogs, said DeWoody, an associate professor of forestry and natural resources.

“In addition to indirect costs of habitat fragmentation, roads have direct costs in terms of animals’ lives,” he said.

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Nature’s great pretenders

April 14, 2008

The firefly, a male Photinus pyralis, winks his best come-on wink as he flies through the summer night: Turning on his light for precisely half a second while swooping upward, he scribes a tiny illuminated “j” in the blackness. Light off, he cruises seven seconds, then—swoop, blink, another “j.” Over and over, he trips his light fantastic in seven-second cadence. On the grass below, an appreciative female answers each “j” three seconds later with a half-second glow, a response that identifies her as a P. pyralis too, and a willing one at that. Encouraged, he draws near and lands next to his newfound mate. The female turns to him, grasps him in her forelegs—and, crushing his body between powerful jaws, devours her would-be lover’s juicy innards.

Such are the dining habits of female Photuris fireflies, a whole different genus. Having cracked the code of the others’ love talk, they lure in tasty Photinus males—and meals—by mimicking the come-hither flashes of Photinus females.

Sneaky? Yes, but hardly unique in nature. Mimicry—the practice of imitating something you’re not to gain some kind of advantage—is widespread. Bugs do it, birds do it, reptiles and amphibians and even mammals do it. It’s a predator-eats-prey world out there, and a little evolved trickery can mean survival.

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Reptile Business Booms As Demand Increases For Unique Pets

April 11, 2008

When we hear the word ‘pet’ most of us conjure up images of finicky felines asserting their independence or fiercely loyal dogs taking on the dual roles of protector and best friend.    But more and more people are choosing less conventional creatures to cohabitate with.  Whether it’s Satanic Leaftail Geckos, Flying Tree Frogs, or slithering Pythons, reptiles and amphibians are no longer the feared curiosities that were once relegated to being used as props in heavy metal videos and horror film.

Grant Crossman can attest to the growing popularity of the unique and awe-inspiring critters.  His store, Port Credit Pet Centre, boasts Canada’s largest selection of reptiles, amphibians, and arachnids, many of which will be on display at the Ontario Reptile And Aquatics Expo, scheduled for April 13th in Mississauga.

“Reptiles are the fastest sector within the pet trade for growth,” Crossman explains.

“It’s the only department in North America that has shown double digit growth in the last three years.  Six percent of all households in the U.S. now own a reptile…in Canada it’s probably about 4 percent.”

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First Lungless Frog Discovered

April 11, 2008

Researchers have confirmed the first case of complete lunglessness in a frog, according to a report in the April 8th issue of Current Biology. The aquatic frog Barbourula kalimantanensis apparently gets all the oxygen it needs through its skin.

Previously known from only two specimens, two new populations of the aquatic frog were found by the team during a recent expedition to Indonesian Borneo.

“We knew that we would have to be very lucky just to find the frog,” said David Bickford of the National University of Singapore. “People have been trying for 30 years. But when we did and I was doing the initial dissections — right there in the field — I have to say that I was very skeptical at first [that they would in fact lack lungs]. It just did not seem possible. We were all shocked when it turned out to be true for all the specimens we had from Kalimantan, Indonesia.

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New Frog Species Found in Kerala

January 20, 2008

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A new species of shrub frog from the Western Ghats adds its name to the growing list of frogs discovered recently. The latest is a tiny oriental shrub frog, named Philautus ochlandrae, discovered in the evergreen forests of the Kakkayam Reserve Forest in Kerala.

The squat little amphibian does not grow beyond 2.5 cm, has a short rounded snout and protruding eyes with striking golden yellow markings. With this, the number of frog species discovered in the last seven years in India stands at 25.The discovery was published in the international journal Zootaxa in October 2007.

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Dog-sized ‘Toadzilla’ captured in Australia

January 10, 2008

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Described as the size of a small dog, the amphibian was found by volunteers searching through bushland near Darwin for cane toads, which are listed as an official pest.

Nicknamed Toadzilla, the reptile’s body is nearly 9in long and it weighs in at almost 2lb – double the size of an average toad.

Now, while a very small dog would be needed to compare it with, Mr Graeme Sawyer, co-ordinator of a toad-catching group called FrogWatch, said the amphibian was the biggest he and his companions had ever seen.

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