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Archive for October, 2007

Brightly Colored Frog Has Dark Future

Posted by Miqe on October 30, 2007

Copywrite Andrew Gray, Manchester Museum

October 30, 2007

Biologists are shining a spotlight on a brightly colored frog whose future looks dark.

The splendid leaf frog (Cruziohyla calcarifer) lives in the tree canopy of the Costa Rican rainforest where it bathes in the tropical sun rays. As is the case with amphibians across the globe, loss of native habitat, environmental change and disease has sent the splendid leaf frog teetering on the brink of extinction.

Scientists from the University of Manchester and the Chester Zoo are teaming up to study the frog species in the field and in the zoo, hoping their findings will not only help save the splendid leaf frog from extinction in the wild but provide clues as to how it can be better catered for in zoos.

“This research aims to contribute to our understanding of the basic factors that influence the development and survival of these frogs,” said project supervisor Richard Preziosi of the University of Manchester in the UK.

“For instance, with the exception of certain mammals, we know surprisingly little about what animals should be eating. And yet the diet of splendid leaf frogs affects their coloration which, in turn, determines their mating behavior.”

The project results could shed light on conservation of other frog species in dire straits. Nearly a third of the world’s 6,000 amphibian species are threatened with extinction and more than 120 species have already vanished from the planet.

The major disease affecting global amphibian populations is caused by the Chytrid fungus which attacks the harder, keratin-rich areas of the animal’s skin, predominantly its feet, before spreading through the rest of its body, almost always with fatal consequences.

From LiveScience

Posted in Amphibians, Herpetology, Herps in the news, International articles and news. | 3 Comments »

Frog killer fungus ‘breakthrough’

Posted by Miqe on October 30, 2007

 

Frog  (Image: Conservation International/Don Church)

The disease has had a devastating impact on frog populations (Conservation Int/D.Church)

New Zealand scientists have found what appears to be a cure for the disease that is responsible for wiping out many of the world’s frog populations.

Chloramphenicol, currently used as an eye ointment for humans, may be a lifesaver for the amphibians, they say.

The researchers found frogs bathed in the solution became resistant to the killer disease, chytridiomycosis.

The fungal disease has been blamed for the extinction of one-third of the 120 species lost since 1980.

Fearful that chytridiomycosis might wipe out New Zealand’s critically endangered Archey’s frog (Leiopelma archeyi), the researchers have been hunting for a compound that would kill off the disease’s trigger, the fungus Batrachochytrium dendrobatidis.

We are losing an awful lot of these creatures now and if we don’t do something intelligent, then we’re going to lose an awful lot more

Professor Russell Poulter,
Researcher

They tested the chloramphenicol candidate on two species introduced to New Zealand from Australia: the brown tree frog (Litoria ewingii) and the southern bell frog (L. raniformis).

“We found that we could cure them completely of chytrids,” said Phil Bishop from the University of Otago.

“And even when they were really sick in the control group, we managed to bring them back almost from the dead.”

“You could put them on their back and they just wouldn’t right themselves, they would just lie there. You could then treat them with chloramphenicol and they would come right,” Dr Bishop explained.

Captive solution

The researchers tried using chloramphenicol as both an ointment, applied to the frogs’ backs, and as a solution.

They found that placing the animals in the solution delivered the best results. The team has admitted it was surprised by the outcome.

“You don’t usually expect antibiotics to do anything to fungi at all. And it does. We don’t understand why it does, but it does,” said Russell Poulter.

WHAT ARE AMPHIBIANS?

Frog (BBC)

Group includes frogs, toads, salamanders and caecilians

First true amphibians evolved about 250m years ago

Adapted to many different aquatic and terrestrial habitats

Present today on every continent except Antarctica

Undergo metamorphosis, from larvae to adults

Professor Poulter, the molecular biologist who hunted down chloramphenicol, added: “It’s also got the great advantage that it’s incredibly cheap.”

The scientists are now making their research widely known ahead of formal publication in a science journal because of the pressing need for a safe and effective treatment for the chytrid disease.

The blow that chytrid has dealt to the frog population is already immense.

The disease has probably accounted for one-third of all the losses in amphibian species to date, says Professor Rick Speare, an expert in amphibian diseases who works with the University of Otago’s frog research group.

These losses are huge – and this is in addition to other threats such as habitat destruction, climate change, pollution and hunting.

Since 1980, more than 120 amphibian species have disappeared; and according to the World Association of Zoos and Aquariums, in the near future many more species are in danger of vanishing.

AMPHIBIANS: THE ASSESSMENT

Salamanders (Conservation International/Don Church)

Conservation Int/D.Church

Amphibians in deep trouble

“We are losing an awful lot of these creatures now and if we don’t do something intelligent, then we’re going to lose an awful lot more,” said Professor Poulter.

But a hopeful finding is that the introduced frogs that have been infected with chytrids are now more resistant to further infections.

“We haven’t quite understood how that could happen,” said Dr Bishop. “It might be a natural thing; if a frog survives a chytrid infection then it is resistant when it gets attacked again.”

The researchers believe that zoos now will have more options, either to be able to control an outbreak or to rescue infected frogs from the wild, knowing that they can be cured.

The next challenge the research team has set itself is to find a treatment that will work in the wild.

“I would really feel quite satisfied if we could say, 10 years from now, that you have to be careful walking around [Australia's] Kosiuszko National Park or you might tread on a corroboree frog because they’re all over the place,” said Professor Poulter. “I would take real satisfaction from that.”

From BBC News

Posted in Amphibians, Herpetology, Herps in the news, International articles and news., Science/Scientific papers | 2 Comments »

Climate change makes south too dry for lizards

Posted by Miqe on October 23, 2007

What has happened to the common lizard?

Alarm bells are sounding in herpetological circles because it seems to be no longer living up to its name in some parts of Britain.

  Male common lizard (top) and female common lizard - pictures by Howard Inns
Male common lizard (top) and female common lizard

While habitat loss from development and intensive agriculture are likely to have had an impact, some experts suspect climate change could be the major cause, with the species possibly no longer feeling at home in increasingly warm and dry southern regions.

Inhabiting particularly grassland, heaths, sandy areas and moors, this species occurs over much of Britain and it is the only type of reptile occurring naturally in Ireland.

Lately, however, there have been reports of it becoming less numerous in – or even disappearing altogether from – areas where formerly there was an abundance.

Howard Inns, of the Herpetological Conservation Trust (HCT), highlights this apparent problem in the current edition of the journal British Wildlife. He is asking naturalists around the country to supply information about how their local populations are faring in an attempt to gauge its extent.

It is hoped the new HCT-led National Reptile Survey which began this year may also throw some light on the problem.

It involves checking on the presence or absence of the four most widespread species in 400 areas spread evenly throughout the country. National trends should be indicated eventually through repeating the exercise annually.

Meanwhile Mr Inns’ own experience this summer points to decline in southern England, where he said it is possible to find all six native species of British reptile in a single morning in Surrey, Dorset and Hampshire, providing the weather is suitable and sites are selected carefully.

Finding a grass snake presents the hardest challenge – while, in contrast, the common lizard is normally encountered more easily.

However, during a field trip to two such sites on an “ideal” spring morning this year, only five of the half-dozen species were encountered. The one that was missing – for no immediately obvious reason – was common lizard.

Had that been a one-off experience it might have been regarded as insignificant but over subsequent months, Mr Inns, an HCT trustee, has heard similar accounts from other parts of the country – which is why he’s trying to gain a firmer impression of what might be happening to the species.

He said: “I have heard of instances of people recording common lizards as infrequently as rarer species.

“My own experience over the past 30 years bears out such reports. I can think of places which used to be alive with baby lizards during August and September but that no longer seems to be the case.

“This would be understandable if the sites had undergone major change but I am aware of such situations in locations where the habitat looks ideal.”

Read the rest of this entry »

Posted in European focus, Fieldherping, Herpetology, Herps in the news, International articles and news., Lacertids, Lizards, Reptiles | Tagged: , , | 1 Comment »

Snake uses trick to avoid poisoning from toxic frogs

Posted by Miqe on October 16, 2007

An Australian snake employs a special feeding behavior to avoid poisoning by toxic frogs, reports The American Naturalist.

University of Sydney scientists Ben Phillips and Richards Shine found that the northern death adder not only distinguishes between different species of toxic frogs, but modifies its feeding behavior to enable it to eat species that rely on different poisons and defensive strategies.

Interested in reading the rest of this article? Please visit Mongabay.com

Posted in Amphibians, Herpetology, Herps in the news, International articles and news., Lizards, Reptiles, Snakes, Venomous herptiles | Leave a Comment »

Caresheet for Lacerta agilis, Sandlizard.

Posted by Miqe on October 15, 2007

I have recently made a caresheet for Lacerta agilis, Sandlizard.

 It can be found om my homepage´s page “Downloads”, or here if you don´t want to see my site. (You don´t know what you´re missing..)

Lacerta agilis pdf.file 57KB

Posted in Caresheets, European focus, Herpetology, Lacertids, Lizards, Reptiles | 2 Comments »

Spinal disease may be key to cane toad eradication

Posted by Miqe on October 15, 2007

(This is a transcript from AM. The program is broadcast around Australia at 08:00 on ABC Local Radio.)

Reporter: Anne Barker

TONY EASTLEY: Scientists have made an intriguing discovery that could help the fight to eradicate cane toads.

They’ve found the fastest toads leading the invasion across northern Australia – they’re the ones with the longest legs – have a remarkably high incidence of spinal disease.

And they’re hoping with a bit of biological engineering they can take even more spring out of the pests’ steps.

Anne Barker reports.

(sound of cane toad call)

ANNE BARKER: In the Top End of Australia, cane toads are getting louder and faster, as the hated pest moves west in ever increasing numbers. But the same speed fuelling their noxious invasion could help bring the toads’ demise.

RICK SHINE: What we’ve discovered is that there’s a real cost to that behaviour, and that the toads at the invasion front have got a remarkably high frequency of spinal arthritis.

ANNE BARKER: Professor of Biology, Rick Shine, says scientists in Darwin recently stumbled on a peculiar phenomenon, that the fastest, fittest toads particularly the ones with the longest legs, often have huge lumps on their backbones, suggesting that those toads leading the invasion are developing serious spinal problems.

RICK SHINE: It’s sort of the mathematics of evolution. Any individual that slows down gets left behind. The only animals you get at the invasion front are the ones that are the descendants of the ones that went fastest, who are in turn the descendants of the ones that went fastest.

And so it’s a cumulative process where any characteristic that enables toads to go quicker and quicker, ends up at the invasion front. And it reaches the stage where it’s pushing the toads’ body plan about as fast… about as far as it can go. And so we start to see these sort of rather horrific spinal problems developing.

ANNE BARKER: It’s giving hope that with a bit of biological tinkering, the toads could at least be slowed down, if not reduced in number

RICK SHINE: The arthritis is partly driven by a soil bacteria that normally it’s all over the place, and it normally doesn’t cause any problems except for people who have got immune problems.

And it looks like the toads’ immune system is under such pressure that they’re actually now vulnerable to attack by these otherwise very benign bacteria. And that kind of gives us a hint that maybe the toads’ immune systems are a real Achilles’ heel that we might be able to exploit in looking for ways to control cane toads.

ANNE BARKER: Professor Shine says researchers are now looking at a worm parasite that afflicts older toads and frogs, to see if it can be developed against the wider toad population.

RICK SHINE: We’ve taken a relatively simple-minded, ecological and behavioural approach, the idea being that rather than jumping out there trying to kill toads, maybe the first step is to try to understand them. And maybe with a better understanding of the ecology of toads we’ll be in a much better position to work out how to control them.

TONY EASTLEY: Professor of Biology, Rick Shine, from Sydney University, speaking with Anne Barker in Darwin.

From ABC

Posted in Amphibians, Herps in the news | 1 Comment »

‘Extinct’ Frog Rediscovered in Costa Rica

Posted by Miqe on October 15, 2007

Isthomhyla rivularis, rediscovered by Andrew Gray and Mark Wainwright in Costa Rica. © The Manchester Museum.Isthomhyla rivularis, rediscovered by Andrew Gray and Mark Wainwright in Costa Rica. © The Manchester Museum.Isthomhyla rivularis, rediscovered by Andrew Gray and Mark Wainwright in Costa Rica. © The Manchester Museum.A critically endangered frog, thought to have become extinct, has just been rediscovered in Costa Rica by Manchester Museum Curator Andrew Gray and local naturalist Mark Wainwright.Isthomhyla rivularis, rediscovered by Andrew Gray and Mark Wainwright in Costa Rica. © The Manchester Museum.After receiving special permission from the Costa Rican authorities to work in the famous Monteverde Cloud Forest Preserve, they were there on to work with rare Green-eyed Frogs, Rana vibicaria, at their last known breeding site. Many amphibian species have dissapeared completely from such high altitude areas over the last twenty five years, where a changing climate and fungal infection are suspected to be the causes. A significant crash in the amphibian population occurred at Monteverde in the late 80’s, when many species dissapeared without trace, including the Golden Toad, Bufo pereglines.

Isthomhyla rivularis, rediscovered by Andrew Gray and Mark Wainwright in Costa Rica. © The Manchester Museum.

16 hour trek
During the 16 hour trek into the remotest part of the reserve, they faced some challenging weather conditionswhich made some sections of the mountain trail particularly trecherous. At one piont, Andrew and Mark, had to cross the middle of a massive landslide where the slightest slip could have proved fatal. Even after an arudous trek, they chose to go looking for frogs at night. It was a decision they did not regret, as this was when they heard a totally unrecognisable frog call.

The frog in question was calling from a high branch and so Andrew had to scale the slippery, moss-covered trunk in his wellington boots, extending his reach precariously along the bough in his effort to retrieve the vocalizing male.

First sighting for 20 years
He said ‘One look at the specimen in my hand and I knew I had caught something very special’. And so he had, for the beautiful brown and metalic-green treefrog was Isthomhyla rivularis – a nocturnal species. The species had dissapeared from Monteverde along with the Golden Toad, almost 20 years ago, and, no-one had seen it since. Although Andrew could have collected the prize specimen, he decided it would only be right to leave it in the wild and, after taking several unique photographs, he released the frog exactly where it was found. The significant find has excited biologist and conservationists around the globe, many of whom have been searching for such a species at Monteverde themselves. It also provides new hope that other species considered to be extinct, such as the Golden Toad, may have also survived and await similar discovery.

Courtesy of Andrew R. Gray, Curator of Herpetology, The Manchester Museum.

From WildlifeExtra

Posted in Amphibians, Fieldherping, Herpetology, Herps in the news, International articles and news. | 1 Comment »

Local kids find 2-headed snake

Posted by Miqe on October 5, 2007

Brothers Jens and Jonah Dancer aren’t easily startled by strange-looking critters. After all, they’ve made a habit of finding all kinds of bugs and snakes to bring home.

But even they were caught off guard Thursday when they realized they had found a two-headed snake.

“When we first saw it, we just thought that it had its mouth open,” 7-year-old Jonah said. “But when we looked closer, we saw the two tongues moving in and out.”

The brothers found the snake while exploring the Devonian Fossil Gorge at Coralville Lake. Their mother, Julie, had brought them there with their little sister, Jae, and baby brother, Jack, to keep them from wasting the day in front of the television set.

Capturing the snake was pretty easy; Jonah just lifted a log and the snake fell into their net. But they had no way to take enough water home with them to keep it alive.

Jae, 4, provided the solution to that problem by lending her brothers one of her boots, which they filled with water from the gorge.

For now, the two-headed reptile is living in an aquarium on the family’s patio. The boys, who are students at Hoover Elementary School in Iowa City, plan to take the snake in for show-and-tell today. They’ll take it back to the gorge after a few days, Jens said.

Julie Dancer said she encourages the boys to pursue their interest in animals.

“Jens loves catching those bugs, and Jonah loves catching those snakes,” she said. “I think Jonah was 3 when he caught his first snake.”

She has laid out some rules, however. The boys are allowed to bring critters home “for observation,” but they eventually must release the animals back into the wild.

Also, “anything comes inside except snakes,” she said. “It’s not coming in the house. Nope. Not going to happen.”

 
Jonah Dancer, 7, holds a two-headed snake that he and his brother, Jens Dancer, 10, found Thursday in the Devonian Fossil Gorge at Coralville Lake.   Press-Citizen / Dan Williamson

 

 


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From Press Citizen

Posted in Fieldherping, Herpetology, Herps in the news, International articles and news., Reptiles, Snake | 1 Comment »

New Species Of Frog Discovered: Smallest Indian Land Vertebrate

Posted by Miqe on October 4, 2007

The India’s smallest land vertebrate, a 10-millimeter frog, has been discovered from the Western Ghats of Kerala by Delhi University Systematics Biologist, S D Biju and his colleagues.


This tiny Indian frog sitting on an Indian 5 rupee coin is the smallest India frog. (Credit: Image courtesy of University of Delhi)

Indian land vertebrates (all animals with backbone except fishes), comprises of 2,400 species including 218 frog species.

S D Biju and his colleagues discovered the tiny night frog living under leaf litter and among the roots of ferns in the humid rainforest of the Western Ghats of Kerala, a mountainous region in the western portion of India. Biju gave a new name for the frog, Nyctibatrachus minimus. 

With adult males of barely 10 mm in length, Nyctibatrachus minimus is the smallest of all known Indian land vertebrates and compete with miniature frogs in other parts of the world, including Cuba, the Amazon and Borneo. 

This frog can be found during nighttime (hence the common name of the genus- Nightfrog) and also can be heard (mating calls) from under the leaf litter during monsoon months, the ideal time for reproduction. 

Biju has been working in the Western Ghats to find new species of frogs over the past several years, and his findings include the purple frog (Nasikabatrachus) and the first canopy frog (Philautus nerostagona) from India. 

The discovery was published recently in the Journal Current Science. 

Note: This story has been adapted from material provided by University of Delhi.

From ScienceDaily

Posted in Amphibians, Herps in the news, International articles and news., Science/Scientific papers | Leave a Comment »

Three-way Mating Game Of North American Lizard Found In Distant European Relative

Posted by Miqe on October 2, 2007

An intricate three-way mating struggle first observed in a species of North American lizard has been discovered in a distant relative, the European common lizard. The two species are separated by 5,000 miles and 175 million years of evolution, yet they share behavioral and reproductive details right down to the gaudy colors of the males, according to new research published in the November issue of American Naturalist.


The three color morphs of European common lizards correspond to different mating strategies. (Credit: Barry Sinervo)

The triangle of competing strategies, which biologists liken to the children’s game rock-paper-scissors, may be far more common than previously recognized–and may even shape the way humans behave, according to lead author Barry Sinervo, professor of ecology and evolutionary biology at the University of California, Santa Cruz.

“The models we propose in this paper are a general phenomenon for all animals, humans included,” Sinervo said. When faced with the task of gathering food or finding mates, he said, “You either cooperate, or take by force, or take by deception. Those are the three ways you can make a living in any social system. It’s one of those basic games that structures life.”

Male European common lizards (Lacerta vivipara) adopt one of those three strategies when pursuing females. A quick look at their undersides reveals the strategy: males who sport orange bellies are brutes who invade other lizards’ territories to mate with any female they can catch. But while they’re gone, drab yellow-bellied males slink onto the vacant territory and mate with unguarded females. White-bellied males guard their mates closely, and cooperate with other white-bellied lizards to keep the yellows at bay. Hence the analogy to rock-paper-scissors: force (orange) defeats cooperation (white), cooperation defeats deception (yellow), and deception defeats force.

Predicted to exist by evolutionary theorists Sewall Wright in 1968 and John Maynard Smith in 1982, rock-paper-scissors games were not discovered in nature until 1996, when Sinervo described the dynamic in the side-blotched lizard (Uta stansburiana) of western North America. Sinervo said he had expected to find other species playing rock-paper-scissors games, too.

“What’s an incredible surprise is that it’s so exactly the same, even right down to the same colors,” he said. “That’s kind of amazing because it says either the game has evolved twice or it’s a game that’s been played since the time of the dinosaurs, when the two species last shared an ancestor.”

There are a few minor differences: in the American lizards the throats, not the bellies, are colored. The white-bellied form in Europe is matched by a blue-throated form in North America–although the two colors are similar in the ultraviolet spectrum, which lizards can see.

To investigate the social strategies of European common lizards, Sinervo and his colleagues spent five years studying lizards at five sites in the Pyrenees mountains of France. They captured more than 250 lizards per year, followed their successes and failures, and ran them on treadmills to gauge their physical prowess. The effect of the social system, they discovered, is a steady cycling of the prevalent color type in the population every four to eight years.

The cycle goes like this: one color type–orange, for example–is common in a patch of habitat for a year or two. During that time, the orange bullies spend their time attacking white-bellied lizards on nearby territories. The effort leaves females on their own territories unguarded, allowing yellow-bellied lizards to sneak in and sire offspring. So yellow males become prevalent for the next year or two. After that, white-bellied lizards proliferate as they team up to protect their mates from yellows’ intrusions. But once the white-bellied males become numerous, they’re easy pickings for the remaining orange-bellied males, who regain superior numbers as the cycle starts again.

Such rock-paper-scissors games may prove to be commonplace throughout the animal kingdom, Sinervo said. The dynamic may just be harder for biologists to find in animals that don’t broadcast their affiliation with bright colors. Mammals, for example, may use scent as their signal.

“I like to think of it this way,” Sinervo said. “If we were Labrador retrievers, maybe we could smell the rock-paper-scissors game all over the place.”

Showy male lizards could be just the most obvious examples. Sinervo speculated that the population booms and busts of lemmings, voles, and hares could come from a similar interplay among reproductive genes in females.

Humans are not immune to the dynamic either. We are far more complex than lizards, but that just means we find more opportunities to adopt the role of aggressor, cooperator, or deceiver. “We play games along an economic axis, a reproductive axis, a familial axis, a political axis. We’ve constructed all this complexity around ourselves,” Sinervo said.

Systems with more than three competing strategies could occur, Sinervo said, but they would tend to simplify themselves into a triangular rock-paper-scissors arrangement because triangular relationships are mathematically more stable.

Sinervo is now trying to map the genes responsible for the behavioral strategies of the European common lizard. This would settle the question as to whether the two species’ last common ancestor engaged in similar struggles back in the time of the earliest dinosaurs. The alternative is that the behavior–and the accompanying color patches–evolved at least twice.

“That tells you how ancient the game is,” Sinervo said. “If the same genes are involved in both species, then it’s been played since the time snakes and lizards diverged. These lizards separated from each other even before the Atlantic ripped open. They may have been playing the same old broken record for 175 million years.”

Sinervo’s coauthors include Benoit Heulin and Yann Surget-Groba of the National Scientific Research Center (CNRS), Paimpont, France; Jean Clobert, of the CNRS Biological Station at Moulis, France; Donald Miles, of Ohio University; UCSC graduate students Ammon Corl and Alison Davis; and former UCSC graduate student Alexis Chaine.

From ScienceDaily

Posted in European focus, Fieldherping, Herpetology, Herps in the news, International articles and news., Lacertids, Lizards, Reptiles | Leave a Comment »

 
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