In 18 countries around the world, biologists are setting out what may be fruitless quests. Conservation International is sponsoring expeditions to seek 40 amphibian species that haven’t been spotted for over a decade, and that may well be extinct. The group hopes its “Search for Lost Frogs” project will draw attention to the plight of amphibians, which are threatened by fungal diseases, toxic chemicals, habitat loss, and climate change–some researchers even say the global population decline is a sign that the world’s sixth mass extinction event is underway.

Dr Robin Moore, of Conservation International, a US-based charity, said: “This role as the global ‘canary in a coalmine’ means that the rapid and profound change to the global environment that has taken place over the last 50 years or so – in particular climate change and habitat loss – has had a devastating impact on these incredible creatures.” [The Guardian]

Still, the biologists hope they’ll find that some of these 40 species are still hanging on. “Although there is no guarantee of success,” Conservation International said in a press release, “scientists are optimistic about the prospect of at least one rediscovery.”

The group also compiled a list of the 10 “most wanted” species. Photo gallery after the jump.

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Five years ago, there were six and a half million little brown bats in the Northeastern United States. In 2020, there may be next to none.

This week in Science, a study models the collapse in bat populations brought on by white-nose syndrome, which was first found in 2006 and is seemingly caused by a nasty fungus. Researchers think that bats with the affliction awaken too early from hibernation, messing up their natural cycles and draining their reserves of energy. A team led by Winifred Frick checked the math on bat population decline and found that they could be locally extinct in many parts of the United States by 2020.

The loss of all these bats would be bad for us, not just them, because they like to dine on pesky insects. So far, researchers have little idea how to cure diseased bats or stop the blight from spreading. The U.S. Forest Service last month proposed to close off abandoned mines in several states, hoping to protect the bats who live in them from the disease. For more about the bats, check out Ed Yong’s Not Exactly Rocket Science.

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Image: Al Hicks, NY DEC

Andrew Crawford and his colleagues discovered 11 new species of amphibians in Panama. But they wish it hadn’t happened this way.

The team just completed a long-term study of amphibians in Panama’s Omar Torrijos National Park, published in the Proceedings of the National Academy of Sciences, showing the startling disappearance of species there. Co-author Karen Lips began the study back before the disease chytridiomycosis, which is caused by a fungus called Batrachochytrium dendrobatidis and has devastated amphibian populations, reached that place and began to afflict its inhabitants.

The pre-decline surveys identified 63 species of amphibians within just a 1.5-square-mile (4-square-kilometer) area. After 2004, 25 of those species had disappeared from the site. As of 2008, none had reappeared. An additional nine species saw an 85 percent to 99 percent decline in their abundance [MSNBC].

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What 15 million years ago was very bad for Australian marsupials is now very good for paleontologists: Researchers have uncovered a death trap, an underground limestone cave where hundreds of animals stumbled to their demise.

A paper published today in Journal of Vertebrate Paleontology details the resulting fossil menagerie, which includes an extinct wombat-like marsupial known as Nimbadon lavarackorum.

Karen Black of the University of New South Wales led the excavation and says in a press release that her team has already uncovered 26 Nimbadon skulls. The varying ages of the skulls detail the Nimbadon‘s whole life cycle from “suckling pouch” to “elderly adults.”

“This is a fantastic and incredibly rare site,” says Dr. Black [regarding the cave]. “The exceptional preservation of the fossils has allowed us to piece together the growth and development of Nimbadon from baby to adult.” [Society of Vertebrate Paleontology]

See a photo gallery of the excavation and fossil processing below the jump.
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In the 1980s, fossil record research showed a curious cycle: Every 27 million years, Earth hosted a mass extinction. Some scientists suggested that a dim star dubbed Nemesis was in a deadly dance with our sun, periodically kicking comets out of the distant Oort Cloud to shower our planet with destruction. Morbidly fascinating as it may be, the authors of a new study argue that this “death star” theory doesn’t hold up.

The cyclical extinctions do make a solid pattern, say Adrian Melott of the University of Kansas and Richard Bambach of Smithsonian Institution Museum of Natural History, whose paper is available through arXiv.org. The two have gone back in the record to 500 million years ago, further than any other researchers, and have confirmed the 27 million year cycle at a 99 percent confidence.

According to Bambach, there’s no doubt at all that every 27 million years-odd, huge numbers of species suddenly become extinct. He says this is confirmed by “two modern, greatly improved paleontological datasets of fossil biodiversity” and that “an excess of extinction events are associated with this periodicity at 99% confidence”. This regular mass slaughter has apparently taken place around 18 times, back into the remote past of half a billion years ago. [The Register]

The problem, Nemesis fans, is that the cycle is too precise, the researchers say. If these extinctions result from a dance between our sun and Nemesis, the researchers note, the period of these mass extinctions would change as other stars buffeted the pair and changed the courses of Nemesis’s orbit around the sun.

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Don’t be fooled by those sinister fangs: For saber-toothed cats, much of the killing power was concentrated in the front limbs.

The long canine teeth that gave the extinct cat its name are an unmistakable feature, protruding from the snarling faces of models in natural history museums everywhere. But while those fangs were deadly, their great length also made them delicate and liable to break if the cat’s prey jostled and writhed in an attempt to escape. Researcher Julie Meachen-Samuels had an idea how such a precarious killing device could have evolved: The cats had incredibly strong front limbs to hold down prey while they used their saber teeth to cut them up.

For a study that appears in the journal PLoS One, the team x-rayed the bones of many saber-toothed cats (Smilodon fatalis), and compared them to a variety of modern-day cats. According to Meachen-Samuels:

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Twelve million years ago, one sperm whale was king. Between 40 and 60 feet in length the beast scientists named Leviathan melvillei wasn’t any bigger than today’s sperm whales, but look at those teeth!

As described in a paper published in Nature today, Olivier Lambert discovered the whale’s fossils in a Peruvian desert. The creature’s name says it all:

[It] combines the Hebrew word ‘Livyatan’, which refers to large mythological sea monsters, with the name of American novelist Herman Melville, who penned Moby-Dick — “one of my favourite sea books”, says lead author Olivier Lambert of the National Museum of Natural History in Paris. [Nature News]

The prehistoric sperm whale may have eaten baleen whales, and its largest chompers are a foot long and some four inches wide. For all the details, check out Ed Yong’s post on Not Exactly Rocket Science.

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Image: Nature

It makes for a good movie: 12,900 years ago, a comet slams into Earth, igniting forest fires across North America and sending the planet into a thousand cold years, killing off mammoths, giant sloths, and a bunch of other big mammals. But scientists have fiercely debated whether such a movie, about the cause of the planet-wide cooling period called the Younger Dryas, should be documentary or science fiction. According to a paper recently published in the Geophysical Research Letters, new evidence–or refuted, old evidence–points to science fiction.

Those that think a comet hit the planet cite “carbonaceous spherules” and nanodiamonds found in sediment from the period of the suspected impact. They argue that these particles formed from the intense heat of the collision.

Lead author of this new study, Andrew Scott of the University of London in Egham suspects those spherules are not from a comet collision, but are bug poop, fungal spores, or charcoal pellets.

From a test that measures how much light the spherules reflect, Scott’s team has determined that the spherules were slow-roasted in a low-intensity heat (perhaps from natural wildfires) instead of in intense, comet impact heat. As shown in the figure, the researchers compare the charred spherules to fungal sclerotia, emergency cell balls created by stressed fungi that can germinate after a bad growing period is over, and saw a striking similarity.

Some of the more elongate particles are “certainly fecal pellets, probably from termites,” says Scott…. “There’s certainly no evidence [that any of these particles are] related to intense fire from a comet impact,” says Scott. Part of the problem, he says, is that “there was nobody [among impact proponents] who ever worked on charcoal deposits, modern or ancient. If you’re not familiar with the material, you can make mistakes.” [Science Now]

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Whither the lizards?

That’s what biologist Barry Sinervo has been asking lately. In a study published on Friday in Science, Sinvero’s team raised the alarm about lizards around the world, saying that at the very least 6 percent of lizard species will go extinct by 2050, and as many as 20 percent could disappear forever by 2080.

Sinervo and his colleagues make this claim based in part on surveys they did in Mexico.

Sinervo and his team surveyed 48 species of spiny lizards at 200 sites on the Yucatan peninsula in Mexico that had been studied in detail from 1975 to 1995 and found that 12 percent of that population had already become extinct by 2009.

The lizards lived in well-protected areas like national parks, so it wasn’t habitat destruction that caused the population decline, Sinervo said. Instead, it was a tale of rising temperatures disrupting lizard lives [San Francisco Chronicle].

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Last week’s meeting of the Convention on International Trade in Endangered Species (CITES) put the spotlight on marine species like the bluefin tuna and some endangered sharks, as the meeting failed to protect them from being overfished to extinction. But a new survey published in the UK journal Mammal Review reminds us that it’s not just marine animals that are endangered by humans, but also primates.

The survey showed that despite CITES’ tight trade regulations for primates, more than a hundred primate species, from gorillas to monkeys to tiny lorises, are endangered by traditional medicine. The survey found that animals across the world were being hunted and killed for their perceived magical or medicinal values–of the 390 species studied, 101, or more than a quarter, are regularly killed for their body parts, with 47 species being used for their supposed medicinal properties, 34 for use in magical or religious practices, and 20 for both purposes [BBC].

The survey found that people still use primate parts to treat a wide variety of ailments. In Bolivia, spider monkey parts are used to cure snake bites, spider bites, fever, coughs, colds, shoulder pain, and sleeping problems; in India, the survey found that many people believe that macaque blood is a cure for asthma. Other monkeys or lorises have their bones or skulls ground up into powder administered with tea, or have their gall bladders ingested or blood or fat used as ointments [BBC]. Monkeys are also valued in Sierra Leone, where a small piece of chimpanzee bone is tied to a child’s waist or wrist, as parents believe it will make the child stronger as he grows older.

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In a victory for East Asian nations that consume sharkfin soup, the Convention on International Trade in Endangered Species (CITES) has shot down three of four proposals to protect sharks. Member nations of CITES who gathered in Doha, Qatar, rejected proposals that would have required countries to strictly regulate — but not ban — trade in several species of scalloped hammerhead, oceanic whitetip and spiny dogfish sharks [The New York Times]. Japan also lobbied against the protections, because it strongly opposes extending the convention’s protections to any marine species (including the bluefin tuna that is so beloved by Japan’s sushi connoisseurs).

The only proposal that managed to get through was a proposal from the European Union and the island nation of Palau to protect the porbeagle shark, which is prized for its meat. But even this victory is a shallow one, as the proposal passed by a margin of just one vote, and could be overturned at the conference’s final session on Thursday.

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Earlier this month, a study in the journal Science tried to put to bed for good the question of dinosaur extinction: It was an impact from space, not large-scale volcanic activity, that wiped them out 65 million years ago, the study argued. That’s all well and good for the dinosaur’s end, but what about their beginning?

This week in the Proceedings of the National Academy of Sciences, paleontologists say they’ve studied the period about 200 million years ago when dinosaurs first came to power, and found that while catastrophic volcanic activity may not explain dinosaur extinction, it could have explained why dinosaurs’ competitors disappeared and the terrible lizards took over the planet.

Around the time of dino emergence, the continents were all locked up in the supercontinent Pangaea. As it pulled apart, researchers say the seismic activity gave rise to hundreds of thousands of years of volcanic activity, creating lava fields on the surface of the Earth the size of the continental United States. For this study, Jessica Whiteside and colleagues surveyed wood remnants, wax from ancient leaves, and whatever else they could extract from the volcanic flow’s remains to reconstruct what was happening in the climate of this period.

The scientists examined how two different isotopes (or forms) of carbon fluctuated during these volcanic eruptions. They found that the “heavy” form of carbon was depleted relative to the “light” form. They say this reflects disturbances in the carbon cycle at this time, including a spike in atmospheric carbon dioxide (CO2) and aerosols (fine solid particles) [BBC News].

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As the deadly facial cancer that has drastically reduced the population of Tasmanian devils continues to spread through the species, the main hope for scientists trying to save them from extinction has been to hunt for devils that might be resistant to the disease, and to try to take advantage of that immunity. Reporting in the Proceedings of the Royal Society B, Kathy Belov and her team say they may finally have done just that: Some devils from northwest Tasmania, they say, are genetically distinct from the rest and could be resistant to the disease.

Belov says that most Tasmanian devils have immune systems so closely related that they’re all susceptible to the disease, which spreads when the devils bite each other on the face and leave behind tumor cells. The bitten devils’ immune systems don’t recognize the tumor cells as foreign, allowing them to take hold. Scientists have given the iconic marsupial as little as 25 years left if efforts are not made to solve the cancer riddle. The population has dwindled by a whopping 70 per cent since the first reported case of devil facial tumour disease in 1996 [Sydney Morning Herald]. Previous research showed that the marsupials are more socially linked that researchers initially believed, which is bad news for those trying to contain the disease.

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An international team of researchers has discovered how to extract DNA from fossilized bird eggs–including the eggshell of the enormous elephant bird that went extinct four centuries ago.

In a research breakthrough, scientists were able to isolate DNA from the eggshells of not just the extinct giant moa bird from New Zealand, but also a 19,000-year-old emu from Australia and the extinct elephant bird of Madagascar. The elephant bird’s egg is the largest known bird egg, with 160 times the volume of a chicken’s egg [New Scientist].

The discovery of these birds’ DNA could help scientists understand how they lived, and why they became extinct. The DNA was extracted from desiccated inner membranes in fossil eggshells, found in 13 locations in Australia, Madagascar and New Zealand [PhysOrg], and the work was published in the Proceedings of the Royal Society B.

For years scientists have been trying to extract DNA from old eggshells without success, because their approach, scientists admit, was faulty. Charlotte Oskam and Michael Bunce of Murdoch University in Perth, Western Australia, who isolated the DNA, say researchers (including themselves) were using techniques designed to extract DNA from bone, not eggshells. They even threw out the most DNA-hardy bits of eggshell [New Scientist]. Bunce explains that extracting DNA from bone involves sucking out the bone’s calcium and discarding it.

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Will we ever get a solid answer on what killed the dinosaurs? According to a new “K-T Boundary Dream Team” comprising of 41 international experts, including geophysicists and paleontologists, yes, the question has been settled: An asteroid is indeed to blame.

For years, scientists have argued over different theories of what killed the dinos–including one hypothesis that has gained ground recently, which suggests that massive volcanic activity in India’s Deccan Traps wiped them out 65 million years ago. However, the latest expert panel stuck to the asteroid theory, saying a massive impact wiped out the dinos and more than half of the Earth’s other species. The panel’s review was published in the journal Science.

After studying all the available data on the Cretaceous-Tertiary (K-T) mass extinction, the panel concluded that the catastrophic event was caused by a 6-mile-wide asteroid that struck Earth at an angle of 90 degrees and a speed of about 12.4 miles per second – about 20 times faster than a speeding bullet [Guardian]. The asteroid hit Chicxulub, Mexico, with a force one billion times more powerful than the atomic bomb at Hiroshima [Science Daily News].

The impact of the crash would have triggered large scale fires, landslides, earthquakes that measured 10 on the Richter scale, and subsequent tsunamis, scientists said. Debris loosened by the impact would have shrouded the planet, clouding the skies, causing a global darkness, and “killing off many species that couldn’t adapt to this hellish environment” [Science Daily News], according to study coauthor Joanna Morgan.

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