At 7mm (0.27 inches) long, Paedophryne amauensis may be the world's smallest vertebrate - the group that includes mammals, fish, birds and amphibians.


World's smallest frog discovered

Richard Black By Richard Black Environment correspondent, BBC News
Frog on coin The tiny frog sits easily on a US dime, whose diameter is 18mm

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A frog species that appears to be the world's smallest has been discovered in Papua New Guinea by a US-based team.


The researchers also found a slightly larger relative, Paedophryne swiftorum.

Presenting the new species in PLoS One journal, they suggest the frogs' tiny scale is linked to their habitat, in leaf litter on the forest floor.

What are amphibians?
Frog eye

First true amphibians evolved about 250 million years ago
Three orders: frogs (inc. toads), salamanders (inc. newts) and the limbless caecilians
Adapted to many aquatic and terrestrial habitats
Present on every continent except Antarctica
Many metamorphose from larvae to adults

Amphibians videos, news and facts: BBC Nature

Finding the frogs was not an easy assignment.

They are well camouflaged among leaves on the forest floor, and have evolved calls resembling those of insects, making them hard to spot.

"The New Guinea forests are incredibly loud at night; and we were trying to record frog calls in the forest, and we were curious as to what these other sounds were," said research leader Chris Austin from Louisiana State University in Baton Rouge, US.

"So we triangulated to where these calls were coming from, and looked through the leaf litter.

"It was night, these things are incredibly small; so what we did after several frustrating attempts was to grab a whole handful of leaf litter and throw it inside a clear plastic bag.

"When we did so, we saw these incredibly tiny frogs hopping around," he told BBC News.
Littering the leaves

The Paedophryne genus was identified only recently, and consists of a number of tiny species found at various points in the eastern forests of Papua New Guinea.
Frog limbs The tiny limbs of amauensis (top) and swiftorum are rendered translucent

"They're occupying the relatively thick leaf litter of tropical forest in low-lying parts of the island, eating incredibly small insects that typically are much smaller than insects that frogs eat," said Professor Austin.

"And they're probably prey for a large number of relatively small invertebrates that don't usually prey on frogs."

Predators may well include scorpions.

Intriguingly, other places in the world that also feature dense, moist leaf litter tend to possess such small frog species, indicating that amphibians are well placed to occupy this ecological niche.

Before the Paedophrynes were found, the title of "world's smallest frog" was bestowed on the Brazilian gold frog (Brachycephalus didactylus) and its slightly larger Cuban relative, the Monte Iberia Eleuth (Eleutherodactylus iberia). They both measure less than 1cm long.

The smallest vertebrates have until now been fish.

Adult Paedocypris progenetica, which dwells in Indonesian swamps and streams, measure 7.9-10.3 mm long.

Male anglerfish of the species Photocorynus spiniceps are just over 6mm long. But they spend their lives fused to the much larger (50mm long) females, so whether they should count in this contest would be disputed.

Paedophryne amaunensis adults average 7.7mm, which is why its discoverers believe it how holds the crown.

The remote expanses of Papua New Guinea rank alongside those of Madagascar as places where hitherto undiscovered amphibian species are expected to turn up, as they are largely undeveloped and not well explored.


http://www.bbc.co.uk/news/science-environment-16491477

Jungle tribes untouched by modern civilisation



http://www.bbc.co.uk/news/magazine-16957988

8 February 2012 Last updated at 23:04 ET Help

They are among the Amazon's last uncontacted tribes and have avoided contact with modern civilisation by hiding in the deepest recesses of the jungle.

Journalist, writer and photographer, Scott Wallace, takes us on a three month journey through the Brazilian Amazon to map the territory of the Arrow People - a rarely glimpsed indigenous group whose life and language remain a mystery and who have repelled previous intruders with deadly arrows.

"The Unconquered - In Search of the Amazon's Last Uncontacted Tribes", explores efforts to protect the rainforest and those who rely on it for survival.

In the book, Brazilian explorer and social activist Sydney Possuelo leads a 34-man team - which includes the author - into the jungle to search for evidence of the Arrow People's range and culture.

In doing so the team must avoid making contact with the tribe, which risks decimation by modern diseases against which it has no protection, should contact be inadvertently made.

Photos: courtesy Scott Wallace and Gleilson Miranda, FUNAI/Survival International

9 February 2012 Last updated at 14:01 ET


Alzheimer's brain plaques 'rapidly cleared' in mice

By James Gallagher Health and science reporter, BBC News

Alzheimer's brain scans Sections of Alzheimer's, left, and healthy brain tissue showing brain shrinkage with the condition


Destructive plaques found in the brains of Alzheimer's patients have been rapidly cleared by researchers testing a cancer drug on mice.

The US study, published in the journal Science, reported the plaques were broken down at "unprecedented" speed.

Tests also showed an improvement in some brain function.

Specialists said the results were promising, but warned that successful drugs in mice often failed to work in people.

The exact cause of Alzheimer's remains unknown, but one of the leading theories involves the formation of clumps of a protein called beta-amyloid. These damage and kill brain cells, eventually resulting in memory problems and the inability to think clearly.

Clearing protein plaques is a major focus of Alzheimer's research and drugs are already being tested in human clinical trials.

In the body, the role of removing beta-amyloid falls to apolipoprotein E - or ApoE. However, people have different versions of the protein. Having the ApoE4 genetic variant is one of the biggest risk factors for developing the disease.
Helping hand

Scientists at the Case Western Reserve University in Ohio were investigating ways of boosting levels of ApoE, which in theory should reduce levels of beta-amyloid.

They tested bexarotene, which has been approved for use to treat cancers in the skin, on mice with an illness similar to Alzheimer's.
Brain plaque Plaques, in brown, form around brain cells, in blue, which kills parts of the brain

After one dose in young mice, the levels of beta-amyloid in the brain were "rapidly lowered" within six hours and a 25% reduction was sustained for 70 hours.

In older mice with established amyloid plaques, seven days of treatment halved the number of plaques in the brain.

The study said there were improvements in brain function after treatment, in nest building, maze performance and remembering electrical shocks.

Researchers Paige Cramer said: "This is an unprecedented finding. Previously, the best existing treatment for Alzheimer's disease in mice required several months to reduce plaque in the brain."
In people?

The research is at a very early stage, and drugs often do not make the leap from animal experiment to human treatment.

Fellow researcher Prof Gary Landreth said the study was "particularly exciting and rewarding" and held the "potential promise of a therapy for Alzheimer's disease".

However, he stressed that the drug had been tested in only three "mouse models" which simulate the early stages of the disease and are not Alzheimer's.
Continue reading the main story
Alzheimer's disease

Alzheimer's disease is the most common cause of dementia
Symptoms include loss of memory, mood changes, and problems with communication and reasoning
No one single factor has been identified as a cause for Alzheimer's disease - a combination of factors, including age, genes, environment, lifestyle and general health are implicated
Source: Alzheimer's Society

He warned people not to "try this at home", as the drug had not been proven to work in Alzheimer's patients and there was no indication of what any dose should be.

"We need to be clear, the drug works quite well in mouse models of the disease. Our next objective is to ascertain if it acts similarly in humans," he said.

His group is preparing to start trials in a small group of people to see if there is a similar effect in humans.

The disease is likely to become more common as people live longer. The Alzheimer's Society predicts the number of people with dementia will reach a million by 2021 in the UK alone.
Continue reading the main story
“Start Quote

There are a number of drugs in development that aim to clear amyloid from the brain, and the jury is still out on whether this approach will be successful as a treatment for Alzheimer's”

Dr Simon Ridley Alzheimer's Research UK

Its research manager, Dr Anne Corbett, said: "This exciting study could be the beginning of a journey towards a potential new way to treat Alzheimer's disease.

"However, this is very early days. People with Alzheimer's should not rush to get this drug, as we need much more research to establish if it has benefits for humans."

Dr Simon Ridley, head of research at Alzheimer's Research UK, said the findings were "promising" but any effect was still unproven in people.

"There are a number of drugs in development that aim to clear amyloid from the brain, and the jury is still out on whether this approach will be successful as a treatment for Alzheimer's."

David Allsop, professor of neuroscience at Lancaster University, said: "I would say that the results should be treated with cautious optimism.

"It looks promising in the mouse model but in recent years, these types of experiments in mice have not translated well into humans."

Balanced on the tip of a scientist's fingernail in Madagascar, the-three centimetre reptile is no bigger than the flies that form his average-sized cousin's lunch. Scientists discovered four new species - called Brookesia micra - on a small islet just off the main island.

Meet mini-meleon! Scientists discover one of the smallest reptiles on the planet

KOOL

Small is good.............................

.

..

4 February 2013 Last updated at 21:57 ET


Sea urchin nickel 'trick' could be key to capturing carbon

By Matt McGrath
Environment correspondent, BBC News

A close up of the skeleton of a sea urchin which could help capture and store carbon
Researchers say that the natural ability of sea urchins to absorb CO2 could be a model for an effective carbon capture and storage system.

Newcastle University scientists discovered by chance that urchins use the metal nickel to turn carbon dioxide into shell.

They say the technique can be harnessed to turn emissions from power plants into the harmless calcium carbonate.

The research is in the journal, Catalysis Science and Technology.


“
Start Quote

The beauty of a nickel catalyst is that it carries on working regardless of the pH....It is also very cheap, a thousand times cheaper than carbon anhydrase”

Gaurav Bhaduri
Newcastle University

Many sea creatures convert carbon dioxide in the waters into calcium carbonate which is essentially chalk. Species such as clams, oysters and corals use it to make their shells and other bony parts.

Bubbling under

When the team at Newcastle looked at the larvae of sea urchins they found that there were high concentrations of nickel on their external skeletons.

Working with extremely small nickel particles, the researchers found that when they added them to a solution of carbon dioxide in water, the nickel completely removed the CO2.

"It is a simple system," Dr Lidija Siller from Newcastle University told BBC News. "You bubble CO2 through the water in which you have nickel nanoparticles and you are trapping much more carbon than you would normally - and then you can easily turn it into calcium carbonate."

"It seems too good to be true, but it works," she added.


An X-ray of a sea urchin embryo shows lots of blue which indicates calcium carbonate

At present most carbon capture and storage (CCS) proposals are based around the idea of capturing CO2 from electricity generating stations or chemical plants and pumping the stripped out gas into underground storage in former oil wells or rock formations.

But there are still question marks about the possibility that the stored carbon may leak back out again.

The Newcastle researchers say that an alternative approach would be to lock up the CO2 in another substance such as calcium carbonate or magnesium carbonate.

This can already be done by using an enzyme called carbon anhydrase but it is very expensive.

PhD student Gaurav Bhaduri who is the lead author on the research paper explained that using nickel would be a far more economic option.


The dominant technology is still the oldest - absorption of carbon dioxide by liquid amines
"The beauty of a nickel catalyst is that it carries on working regardless of the pH and because of its magnetic properties it can be re-captured and re-used time and time again," he said.

"It is also very cheap, a thousand times cheaper than carbon anhydrase. And the by-product - the carbonate - is useful and not damaging to the environment."

Calcium carbonate is said to make up 4% of the earth's crust.

By JOHN NOBLE WILFORD
Published: February 7, 2013 107 Comments


Humankind’s common ancestor with other mammals may have been a roughly rat-size animal that weighed no more than a half a pound, had a long furry tail and lived on insects.


Illustration by Carl Buell

An artist’s rendering of a placental ancestor. Researchers say the small, insect-eating animal is the most likely common ancestor of the species on the most abundant and diverse branch of the mammalian family tree.



S. Goldberg, M. Novacek/AMNH
Another Cretaceous-age animal found in the Gobi Desert in 1994, one of many used to study the mammalian tree of life.


In a comprehensive six-year study of the mammalian family tree, scientists have identified and reconstructed what they say is the most likely common ancestor of the many species on the most abundant and diverse branch of that tree — the branch of creatures that nourish their young in utero through a placenta. The work appears to support the view that in the global extinctions some 66 million years ago, all non-avian dinosaurs had to die for mammals to flourish.

Scientists had been searching for just such a common genealogical link and have found it in a lowly occupant of the fossil record, Protungulatum donnae, that until now has been so obscure that it lacks a colloquial nickname. But as researchers reported Thursday in the journal Science, the animal had several anatomical characteristics for live births that anticipated all placental mammals and led to some 5,400 living species, from shrews to elephants, bats to whales, cats to dogs and, not least, humans.

A team of researchers described the discovery as an important insight into the pattern and timing of early mammal life and a demonstration of the capabilities of a new system for handling copious amounts of fossil and genetic data in the service of evolutionary biology. The formidable new technology is expected to be widely applied in years ahead to similar investigations of plants, insects, fish and fowl.

Given some belated stature by an artist’s brush, the animal hardly looks the part of a progenitor of so many mammals (which do not include marsupials, like kangaroos and opossums, or monotremes, egg-laying mammals like the duck-billed platypus).

Maureen A. O’Leary of Stony Brook University on Long Island, a leader of the project and the principal author of the journal report, wrote that a combination of genetic and anatomical data established that the ancestor emerged within 200,000 to 400,000 years after the great dying at the end of the Cretaceous period. At the time, the meek were rapidly inheriting the earth from hulking predators like T. rex.

Within another two million to three million years, Dr. O’Leary said, the first members of modern placental orders appeared in such profusion that researchers have started to refer to the explosive model of mammalian evolution. The common ancestor itself appeared more than 36 million years later than had been estimated based on genetic data alone.

Although some small primitive mammals had lived in the shadow of the great Cretaceous reptiles, the scientists could not find evidence supporting an earlier hypothesis that up to 39 mammalian lineages survived to enter the post-extinction world. Only the stem lineage to Placentalia, they said, appeared to hang on through the catastrophe, generally associated with climate change after an asteroid crashed into Earth.

The research team drew on combined fossil evidence and genetic data encoded in DNA in evaluating the ancestor’s standing as an early placental mammal. Among characteristics associated with full-term live births, the Protungulatum species was found to have a two-horned uterus and a placenta in which the maternal blood came in close contact with the membranes surrounding the fetus, as in humans.

The ancestor’s younger age, the scientists said, ruled out the breakup of the supercontinent of Gondwana around 120 million years ago as a direct factor in the diversification of mammals, as has sometimes been speculated. Evidence of the common ancestor was found in North America, but the animal may have existed on other continents as well.

The publicly accessible database responsible for the findings is called MorphoBank, with advanced software for handling the largest compilation yet of data and images on mammals living and extinct. “This has stretched our own expertise,” Dr. O’Leary, an anatomist, said in an interview.

(Page 2 of 2)

“The findings were not a total surprise,” she said. “But it’s an important discovery because it relies on lots of information from fossils and also molecular data. Other scientists, at least a thousand, some from other countries, are already signing up to use MorphoBank.”


Michael J. Novacek, a paleontologist and provost for science at the American Museum of Natural History in New York City, said the system could assess each mammal on the basis of more than 4,500 possible traits, which is 10 times larger than previous databases. “At one point, I didn’t think we would ever finish,” Dr. Novacek said.

John R. Wible, curator of mammals at the Carnegie Museum of Natural History in Pittsburgh, who is another of the 22 members of the project, said the “power of 4,500 characters” enabled the scientists to look “at all aspects of mammalian anatomy, from the skull and skeleton, to the teeth, to internal organs, to muscles and even fur patterns” to determine what the common ancestor possibly looked like.

The project was financed primarily by the National Science Foundation as part of its Assembling the Tree of Life program. Other scientists from Stony Brook, the American Natural History Museum and the Carnegie Museum participated, as well as researchers from the University of Florida, the University of Tennessee at Chattanooga, the University of Louisville, Western University of Health Sciences, in Pomona, Calif., Yale University and others in Canada, China, Brazil and Argentina.

Outside scientists said that this formidable new systematic data-crunching capability might reshape mammal research but that it would probably not immediately resolve the years of dispute between fossil and genetic partisans over when placental mammals arose. Paleontologists looking for answers in skeletons and anatomy have favored a date just before or a little after the Cretaceous extinction. Those who work with genetic data to tell time by “molecular clocks” have arrived at much earlier origins.

The conflict was billed as “Fossils vs. Clocks” in the headline for a commentary article by Anne D. Yoder, an evolutionary biologist at Duke University, which accompanied Dr. O’Leary’s journal report.

Dr. Yoder acknowledged that the new study offered “a fresh perspective on the pattern and timing of mammalian evolution drawn from a remarkable arsenal of morphological data from fossil and living mammals.” She also praised the research’s “level of sophistication and meticulous analysis.”

Even so, Dr. Yoder complained that the researchers “devoted most of their analytical energy to scoring characteristics and estimating the shape of the tree rather than the length of its branches.” She said that “the disregard for the consequences of branch lengths,” as determined by the molecular clocks of genetics, “leaves us wanting more.”

John Gatesy, an evolutionary biologist at the University of California, Riverside, who was familiar with the study but was not an author of the report, said the reconstruction of the common ancestor was “very reasonable and very cool.” The researchers, he said, “have used their extraordinarily large analysis to predict what this earliest placental looked like, and it would be interesting to extend this approach to more branch points in the tree” including for early ancestors like aardvarks, elephants and manatees.

But Dr. Gatesy said the post-Cretaceous date for the placentals “will surely be controversial, as this is much younger than estimates based on molecular clocks, and implies the compression of very long molecular branches at the base of the tree.”

http://www.nytimes.com/2013/02/08/science/common-ancestor-of-mammals-plucked-from-obscurity.html?pagewanted=2&_r=0&hpw