MOSCOW (AP) ? A former National Security Agency contractor wanted by the United States for revealing highly classified surveillance programs was believed to have landed in Russia on Sunday ? possibly as a stopover before traveling elsewhere ? after being allowed to leave Hong Kong.
Edward Snowden was on an Aeroflot flight from Hong Kong that arrived in Moscow shortly after 5 p.m. (1300gmt) Sunday and was booked on a flight to fly to Cuba on Monday, the Russian news agencies ITAR-Tass and Interfax reported, citing unnamed airline officials. The reports said he intended to travel from Cuba to Caracas, Venezuela. There was also speculation that he might try to reach Ecuador.
The WikiLeaks anti-secrecy group said it was working with him and that he was bound for an unnamed "democratic nation via a safe route for the purpose of asylum."
Snowden did not leave Moscow's Sheremetyevo Airport with the other passengers and was not seen by a crowd of journalists waiting in the arrivals lounge. Interfax reported that he was spending the night in the transit zone of the airport because he did not have a visa to enter Russia and had rented a room in a capsule hotel.
The car of Ecuador's ambassador to Russia was parked outside the airport, spurring the speculation that Snowden intended to seek asylum in the Latin American country. But in Ecuador, a high-ranking source at the presidency said there was no information about whether Snowden would seek asylum there. The source spoke on condition of anonymity for lack of authorization to speak on the issue.
Foreign Minister Ricardo Patino said last week that if Snowden asked for asylum, Ecuador would study the request.
Snowden had been in hiding in Hong Kong for several weeks after he revealed information on the highly classified spy programs. WikiLeaks said it was providing legal help to Snowden at his request and that he was being escorted by diplomats and legal advisers from the group.
WikiLeaks' founder, Julian Assange, who has spent a year inside the Ecuadorean Embassy in London to avoid extradition to Sweden to face questioning about sex crime allegations, told the Sydney Morning Herald that his organization is in a position to help because it has expertise in international asylum and extradition law.
The White House said President Barack Obama has been briefed on Sunday's developments by his national security advisers.
Snowden's departure came a day after the United States made a formal request for his extradition and gave a pointed warning to Hong Kong against delaying the process of returning him to face trial in the U.S.
The Department of Justice said only that it would "continue to discuss this matter with Hong Kong and pursue relevant law enforcement cooperation with other countries where Mr. Snowden may be attempting to travel."
The Hong Kong government said in a statement that Snowden left "on his own accord for a third country through a lawful and normal channel."
It acknowledged the U.S. extradition request, but said U.S. documentation did not "fully comply with the legal requirements under Hong Kong law." It said additional information was requested from Washington, but since the Hong Kong government "has yet to have sufficient information to process the request for provisional warrant of arrest, there is no legal basis to restrict Mr. Snowden from leaving Hong Kong."
The statement said Hong Kong had informed the U.S. of Snowden's departure. It added that it wanted more information about alleged hacking of computer systems in Hong Kong by U.S. government agencies which Snowden had revealed.
Hong Kong's decision to let Snowden go on a technicality appears to be a pragmatic move aimed at avoiding a drawn out extradition battle. The action swiftly eliminates a geopolitical headache that could have left Hong Kong facing pressure from both Washington and Beijing.
Hong Kong, a former British colony, has a high degree of autonomy and is granted rights and freedoms not seen on mainland China, but under the city's mini constitution Beijing is allowed to intervene in matters involving defense and diplomatic affairs.
Hong Kong has an extradition treaty with the U.S., but the document has some exceptions, including for crimes deemed political.
Russian officials have given no indication that they have any interest in detaining Snowden or any grounds to do so. Foreign Minister Sergey Lavrov has said that Russia would be willing to consider granting asylum if Snowden were to make such a request.
Russia and the United States have no extradition treaty that would oblige Russia to hand over a U.S. citizen at Washington's request.
The Cuban government had no comment on Snowden's movements or reports he might use Havana as a transit point.
The Obama administration on Saturday warned Hong Kong against delaying Snowden's extradition, with White House national security adviser Tom Donilon saying in an interview with CBS News, "Hong Kong has been a historically good partner of the United States in law enforcement matters, and we expect them to comply with the treaty in this case."
Michael Ratner, Assange's lawyer, said he didn't know Snowden's final destination, but that his options were not numerous. "You have to have a country that's going to stand up to the United States," Ratner said. "You're not talking about a huge range of countries here."
Ratner added that a country's extradition treaty with the U.S. is "not going to be relevant" because the country he ends up going to will likely be one willing to give him a political exemption.
Snowden's departure came as the South China Morning Post released new allegations from the former NSA contractor that U.S. hacking targets in China included the nation's cellphone companies and two universities hosting extensive Internet traffic hubs.
He told the newspaper that "the NSA does all kinds of things like hack Chinese cellphone companies to steal all of your SMS data." It added that Snowden said he had documents to support the hacking allegations, but the report did not identify the documents. It said he spoke to the newspaper in a June 12 interview.
With a population of more than 1.3 billion, China has massive cellphone companies. China Mobile is the world's largest mobile network carrier with 735 million subscribers, followed by China Unicom with 258 million users and China Telecom with 172 million users.
Snowden said Tsinghua University in Beijing and Chinese University in Hong Kong, home of some of the country's major Internet traffic hubs, were targets of extensive hacking by U.S. spies this year. He said the NSA was focusing on so-called "network backbones" in China, through which enormous amounts of Internet data passes.
The Chinese Foreign Ministry said it was aware of the reports of Snowden's departure from Hong Kong to Moscow but did not know the specifics. It said the Chinese central government "always respects" Hong Kong's "handling of affairs in accordance with law." The Foreign Ministry also noted that it is "gravely concerned about the recently disclosed cyberattacks by relevant U.S. government agencies against China."
China's state-run media have used Snowden's allegations to poke back at Washington after the U.S. had spent the past several months pressuring China on its international spying operations.
A commentary published Sunday by the official Xinhua News Agency said Snowden's disclosures of U.S. spying activities in China have "put Washington in a really awkward situation."
"Washington should come clean about its record first. It owes ... an explanation to China and other countries it has allegedly spied on," it said. "It has to share with the world the range, extent and intent of its clandestine hacking programs."
____
Chan reported from Hong Kong. Sylvia Hui in London, Paul Haven in Havana, Gonzalo Solano in Quito, Ecuador, and Anne Flaherty and Julie Pace in Washington contributed to this report.
June 21, 2013 ? Researchers in Berlin and Munich, Germany and Oxford, United Kingdom, have revealed that a protein well known for its role in Alzheimer's disease controls spindle development in muscle and leads to impaired movement in mice when the protein is absent or treated with inhibitors. The results, which are published in The EMBO Journal, suggest that drugs under development to target the beta-secretase-1 protein, which may be potential treatments for Alzheimer's disease, might produce unwanted side effects related to defective movement.
Alzheimer's disease is the most common form of dementia found in older adults. The World Health Organization estimates that approximately 18 million people worldwide have Alzheimer's disease. The number of people affected by the disease may increase to 34 million by 2025. Scientists know that the protein beta-secretase-1 or Bace1, a protease enzyme that breaks down proteins into smaller molecules, is involved in Alzheimer's disease. Bace1 cleaves the amyloid precursor protein and generates the damaging Abeta peptides that accumulate as plaques in the brain leading to disease. Now scientists have revealed in more detail how Bace1 works.
"Our results show that mice that lack Bace1 proteins or are treated with inhibitors of the enzyme have difficulties in coordination and walking and also show reduced muscle strength," remarked Carmen Birchmeier, one of the authors of the paper, Professor at the Max-Delbr?ck-Center for Molecular Medicine in Berlin, Germany, and an EMBO Member. "In addition, we were able to show that the combined activities of Bace1 and another protein, neuregulin-1 or Nrg1, are needed to sustain the muscle spindles in mice and to maintain motor coordination."
Muscle spindles are sensory organs that are found throughout the muscles of vertebrates. They are able to detect how muscles stretch and convey the perception of body position to the brain. The researchers used genetic analyses, biochemical studies and interference with pharmacological inhibitors to investigate how Bace1 works in mice. "If the signal strength of a specific form of neuregulin-1 known as IgNrg1 is gradually reduced, increasingly severe defects in the formation and maturation of muscle spindles are observed in mice. Furthermore, it appears that Bace1 is required for full IgNrg1 activity. The graded loss of IgNrg1 activity results in the animals having increasing difficulties with movement and coordination," says Cyril Cheret, the first author of the work.
Drug developers are interested in stopping the Bace1 protein in its tracks because it represents a promising route to treat Alzheimer's disease. If the protein were inhibited, it would interfere with the generation of the smaller damaging proteins that accumulate in the brain as amyloid plaques and would therefore provide some level of protection from the effects of the disease. "Our data indicate that one unwanted side effect of the long-term inhibition of Bace1 might be the disruption of muscle spindle formation and impairment of movement. This finding is relevant to scientists looking for ways to develop drugs that target the Bace1 protein and should be considered," says Birchmeier. Several Bace1 inhibitors are currently being tested in phase II and phase III clinical trials for the treatment of Alzheimer's disease.
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The above story is reprinted from materials provided by European Molecular Biology Organization, via EurekAlert!, a service of AAAS.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Cyril Cheret, Michael Willem, Florence R Fricker, Hagen Wende, Annika Wulf-Goldenberg, Sabina Tahirovic, Klaus-Armin Nave, Paul Saftig, Christian Haass, Alistair N Garratt, David L Bennett, Carmen Birchmeier. Bace1 and Neuregulin-1 cooperate to control formation and maintenance of muscle spindles. The EMBO Journal, 2013; DOI: 10.1038/emboj.2013.146
Note: If no author is given, the source is cited instead.
Facebook says a bug in its system caused 6 million users' contact information to be inadvertently exposed.
The social media company said Friday that a bug led to users' contact information, such as email addresses or phone numbers, to be accessed by other users who either had some contact information about that person or some connection to them.
Facebook said in a blog post that the cause of the bug is "pretty technical" but that the problem is tied to its "Download Your Information" tool.
The company uses the information that users upload to better tailor the friend suggestions it issues. The bug caused some of this information to be inadvertently stored in association with a person's contact information as part of their Facebook account.
As a result, if someone downloaded an archive of their Facebook account through the "Download Your Information" tool, they may have been provided with additional addresses or telephone numbers for their contacts or people with whom they have some connection. Because the contact information was provided by other people on Facebook, it was not necessarily accurate.
Facebook said it has fixed the problem and is in the process of notifying affected users via email.
The affected accounts represent only a fraction of the over 1 billion users on the social media site.
Facebook, which is headquartered in Menlo Park, Calif., said that it has no evidence that the bug has been used maliciously and it has not received complaints.
**** Dave Jaram? We hadn?t heard of him either. Turns out he?s the quiet man of fine dining but his food is worth shouting about, says Andy Richardson.
I?ve long been puzzled by the low profile of one of Shropshire?s finest chefs. Dave Jaram, head chef at Fishmore Hall, in Ludlow, rates barely a mention when awards are conferred, TV talent spotters come a-callin? or when chefs are lined up to demonstrate at the county?s food festivals.
He?s the invisible man, it seems. He?s a chef who stays in his kitchen, who barely ventures out.
It?s a curious state of affairs given Jaram?s obvious talent. The capable head chef has a passion for dishes that feature the very best of local, seasonal produce and has been dazzling Fishmore Hall guests for some years.
He came to the venue with an impressive pedigree, having worked at the acclaimed Close Hotel, in Tetbury, under head chef Daren Bale and then at Newbury Manor under head chef Simon McKenzie.
He acquired further experience in Cheshire, where he joined the team at the acclaimed Nunsmere Hall under Nigel Goodwin, and sous chef Marc Hardiman, before making further stops at The Haycock in Wansford and The Greenway in Cheltenham.
As CVs go, Jaram?s ain?t bad.
But it?s his work at Fishmore Hall that has helped him to earn an enviable reputation. He has developed impressive contacts with local suppliers, whose food and drink he showcases on ever-changing menus that reflect the best of seasonal, abundant produce.
And yet. And yet. Jaram seems to barely register when newspaper articles are written or when local chefs are called upon to demonstrate the county?s exceptional food. Maybe he?s a quiet fella, maybe he avoids the limelight for the security of his kitchen or maybe it?s down to bad PR ? for us newspaper boys and girls are seldom encouraged to write about him. Whatever the reason, Jaram is a chef that too few people have heard of. So let?s try and put that right.
Jaram?s classy food is at the heart of Fishmore Hall. Yes, there are stunning views across surrounding countryside, yes the service is of a high standard and features a surprisingly cohesive young team and yes the provenance of Jaram?s ingredients is first class. But the reason for the venue?s excellence is clear to see: it has a really good chef.
I?ve eaten at Fishmore Hall on too few occasions. In recent years, there have been times when it has dazzled, when it?s been a shoo-in for my Top Five restaurants in the county. Innovative flavours, contrasting textures, stunning presentation and perfectly matched ingredients have been incredibly impressive.
My friend and I paid our most recent visit to enjoy a midweek dinner and there was much to enjoy.
We arrived early, just after 7pm, and there was only one other couple there. They were celebrating an elevation to being chair of some such board and were perusing an impressive wine list. After entering the venue, we were shown to deep, comfortable sofas, where we relaxed with pre-dinner drinks.
The menus were impressive. They featured the best seasonal flavours of Shropshire: a saddle of rabbit, a loin of spring lamb, venison from nearby woods and deliciously gamey pigeon, among others.
We were greeted warmly by a youthful maitr? d?, who proved herself a star act throughout our evening.
Our canap?s arrived: a sunblush tomato hummus with crispy bread slices and two beignets of goat?s cheese mousse with chive. The hummus was delicious: satisfying and piquant, it was scooped up and dispatched before we could say: ?Dave Jaram ought to be more widely known, you know, because he?s really rather good?. The beignets were less impressive. Beyond their crunchy, breaded outer layer was a too-salty goat?s cheese filling.
We were then shown in to the dining room where we enjoyed a small cup of cauliflower veloute with a truffle oil. It was pretty good, without being exceptional. The flavours of the cauliflower were a little too abrupt; they were overly pronounced, though the delightfully earthy truffle oil was a perfect compliment.
My friend had to be careful about what to choose from the menu, given that she was midway through a pregnancy. Happily, Fishmore Hall?s thoughtful staff made sure there were no demons on her plate: they were attentive throughout our dinner.
She started with a chicken mousse that was served with cubes of salt-baked beetroot, an asparagus mousse, tiny cubes of cooked lemon and micro herbs. It was delightful. The subtle, grassy asparagus mousse provided a sweet, seasonal accompaniment to the deliciously tender and moist chicken while the sharp, citrusy lemon cut through its natural richness. The micro herbs seemed to be present for garnish, rather than to add flavour. It looked as pretty as a picture and she enjoyed it enormously.
I opted for a pigeon starter, which was served with a wild mushroom risotto. It was presented with great skill, the fillet of the pigeon?s breast being cut into thin slices and laid over the unctuous risotto. The flavours were superb.
My main course was an exploration of all things pork. Tiny rounds of fillet were wrapped in bacon, pan-fried and then slow-cooked. They were tender and delicious. A slither of pork belly had been cooked with skill, so that the fat rendered through the meat and gave it a lustrous texture and extravagant flavour. A small, crunchily-coated potato croquette added contrast while tiny balls of apple and swishes of vegetable puree added to the dish. It was delightful. Presented on a vast plate, almost as large as a football pitch, each component had been neatly arranged. It was as though Jaram was playing some sort of Chef Jenga and we had to work out a magic code.
My friend?s main dish was also good. A large piece of cod sat on a bed of linguine with saffron sauce. She had asked the waitresses to omit a mussel component, which they readily did. The cod had been cooked with finesse.
We enjoyed a brief break before our desserts, which were a little underwhelming. My friend had chosen the bread and butter souffl?, with tonka bean ice cream, while I had opted for an exploration of caramel, comprising a mousse, sauce and gel, paired with almond ice cream and a delightful biscotti.
Just before my friend?s souffl? had been due to arrive, the waitress returned. ?We don?t think we ought to serve it,? they said. ?The egg will still be a little moist and perhaps you ought not eat it.? She was grateful for their consideration and thoughtfulness and opted for a plate of homemade ice creams instead.
My caramel dessert was presented with aplomb but was a little lacking in contrast. The almond biscotti was the highlight, though the mousse was not packed with flavour.
Fishmore Hall isn?t cheap. Our three course a la carte menu came in at ?50 per head, a far higher price that one might expect to pay at comparable venues. Jaram?s cooking and a highly-polished brigade make that almost worthwhile. Far better value is Jaram?s six-course tasting menu, at ?59. However, the prices are still high, given that nine-courses at the Michelin-starred Mr Underhill?s is ?65.
Service was efficient and relaxed. Waitresses were polite and attentive throughout, asking whether we?d enjoyed our dinners and making regular visits to our table to pour drinks. They were classy performers.
The views form the dining room were also exquisite. A purpose-built conservatory-style venue sits slap bang in the middle of verdant, rolling countryside. Throughout our dinner we enjoyed wonderful views as the sun slowly sank and the colours changed. We seemed to enjoy a thousand variations of the same view; with blues, gold, green and similar colours honing into view.
Jaram?s cooking was exquisite though, in truth, it did not match the same standards as Ludlow?s ? and Shropshire?s ? two best restaurants: the nearby Mr Underhill?s and Will Holland?s La Becasse. Both offer greater flavour, more original flavour combinations and presentation that is of a higher standard. And, crucially, both offer better value.
No matter, Jaram remains in the upper echelons on the local dining scene. A smooth operator capable of technical excellence and impressive presentation.
Contact: Erna van Wyk erna.vanwyk@wits.ac.za 27-011-717-4023 University of the Witwatersrand
Amphibian and mammal forerunner share 250 million year old burrow
Synchrotron imaging reveals odd couple - 250 million years ago, a mammal forerunner and an amphibian shared a burrow.
Scientists from South Africa, Australia and France have discovered a world first association while scanning a 250 million year old fossilized burrow from the Karoo Basin of South Africa.
The burrow revealed two unrelated vertebrate animals nestled together and fossilized after being trapped by a flash flood event. Facing harsh climatic conditions subsequent to the Permo-Triassic (P-T) mass extinction, the amphibian Broomistega and the mammal forerunner Thrinaxodon cohabited in a burrow.
Scanning shows that the amphibian, which was suffering from broken ribs, crawled into a sleeping mammal's shelter for protection. This research suggests that short periods of dormancy, called aestivation, in addition to burrowing behavior, may have been a crucial adaptation that allowed mammal ancestors to survive the P-T extinction.
The results of this research resulted in a paper entitled Synchrotron reveals Early Triassic odd couple: injured amphibian and aestivating therapsid share burrow and that is published in the scientific journal, PLoS ONE, on Friday, 21 June 2013 at 23:00 SA Standard Time.
The international team of scientists was led by Dr Vincent Fernandez from Wits University, South Africa and the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The other authors from Wits University include Prof. Bruce Rubidge (Director of the newly formed Palaeosciences Centre of Excellence at Wits), Dr Fernando Abdala and Dr Kristian Carlson. Other authors include Dr Della Collins Cook (Indiana University); Dr Adam Yates (Museum of Central Australia) and Dr. Paul Tafforeau (ESRF).
After many impressive results obtained on fossils, synchrotron imaging has led to revived interest in the studies of the numerous fossilized burrows discovered in the Karoo Basin of South Africa and dated to 250 million years ago. The first attempt to investigate one of these burrow-casts surprisingly revealed a world-first association of two unrelated animals.
The fossil was recovered from sedimentary rock strata in the Karoo Basin. It dates from 250 million years ago, at the beginning of the Triassic Period. At that time, the ecosystem was recovering from the Permo-Triassic mass extinction that wiped out most of life on Earth. In the Pangea Supercontinent context, what is now South Africa was an enclave in the southern half called Gondwana. It was the scene of pronounced climatic warming and increased seasonality marked by monsoonal rainfall. To survive this harsh environment, many animals, including mammal-like reptiles (mammal forerunners), developed a digging behavior, attested by the numerous fossilized burrow casts discovered in the Karoo Basin. These casts have long been thought to enclose fossilized remains, triggering interest from palaeontologists. Early this year, an international group of scientists started to research the contents of these burrows using X-ray synchrotron computed microtomography.
Two burrow casts were selected from the collection at Wits to be scanned using the state-of-the-art facility at the European Synchrotron Radiation Facility (ESRF). Using the unique properties of the X-ray beam which enables non-destructive probing, the scan of the first burrow started to reveal the skull of a mammal-like reptile called Thrinaxodon, an animal previously reported in another burrow.
As the scan progressed, the three-dimensional reconstruction displayed results beyond expectations: the mammal-like reptile was accompanied by an amphibian Broomistega, belonging to the extinct group of Temnospondyl.
"While discovering the results we were amazed by the quality of the images", says lead author Fernandez, "but the real excitement came when we discovered a second set of teeth completely different from that of the mammal-like reptile. It was really something else".
Besides the pristine preservation of the two skeletons, the team focused on the reasons explaining such an unusual co-habitation. Fernandez explains: "Burrow-sharing by different species exists in the modern world, but it corresponds to a specific pattern. For example, a small visitor is not going to disturb the host. A large visitor can be accepted by the host if it provides some help, like predator vigilance. But neither of these patterns corresponds to what we have discovered in this fossilized burrow".
The scientists gathered all the information to try to reconstitute the events that led to this incredible fossil aggregation, testing scenarios one after another. "It's a fascinating scientific question: what caused the association of these two organisms in the burrow? One of the more obvious possibilities is a predator-prey interaction, but we inspected both skeletons looking for tooth marks or other evidence implying predation, ultimately finding no support for one having attempted to feed on the other," says Carlson.
His colleague, Cook, adds that the consecutive broken ribs resulted from a single, massive trauma. The amphibian clearly survived the injury for some time because the fractures were healing, but it was surely quite handicapped. According to Fernandez this Broomistega is the first complete skeleton of this rare species that has been discovered. "It tells us that this individual was a juvenile and mostly aquatic at that time of its life," he says.
The scientists eventually concluded that the amphibian crawled into the burrow in response to its poor physical condition but was not evicted by the mammal-like reptile.
Numerous Thrinaxodon specimens have been found in South Africa, many of them fossilized in a curled-up position. Abdala says: "I have always been fascinated by the preservation of Thrinaxodon fossils in a curled-up position that show even tiny bones of the skeleton preserved. It's as if they were peacefully resting in shelters at the time of death".
The shelters prevented disturbance of the skeletal remains from scavengers and weathering. "We also think it might reflect a state of torpor called aestivation in response to aridity and absence of food resources," Abdala says.
Piecing all the clues together, the team finally elucidated the enigmatic association, concluding that "the mammal-like reptile, Thrinaxodon, was most probably aestivating in its burrow, a key adaptation response together with a burrowing behavior which enabled our distant ancestors to survive the most dramatic mass extinction event. This state of torpor explains why the amphibian was not chased out of the burrow," says Rubidge.
Both animals were finally entrapped in the burrow by a sudden flood and preserved together in the sediments for 250 million years.
Tafforeau says: "Thanks to the unique possibilities for high quality imaging of fossils developed during the last decade at the ESRF, these unique specimens remain untouched, protected by their mineral matrix. Who knows what kind of information we'll be able to obtain from them in the future and which would have been completely lost if the specimen had been prepared out of its burrow cast?"
###
TO INTERVIEW WITS RESEARCHERS:
Dr Vincent Fernandez
European Synchrotron Radiation Facility, France
Evolutionary Studies Institute, Wits University
Tel: +33 4 76 88 28 56 or +33 6 95 57 68 96
Email: vincent.fernandez@esrf.fr
Dr Kristian Carlson
Evolutionary Studies Institute, Wits University
Tel +27 (0) 11 717 6681 or +27 (0) 73 666 0106
Email: Kristian.Carlson@wits.ac.za
Prof. Bruce Rubidge
Director for the Centre for Excellence in Palaeosciences as well as the Evolutionary Studies Institute, Wits University
Tel +27 (0) 11 717 6685 or +27 (0) 72 575 7752
Email: Bruce.Rubidge@wits.ac.za
Issued by:
Claus Habfast
ESRF
Grenoble, France
Head of Communication Group
Tel +33 4 7688 2128 or +33 666 662 384 claus.habfast@esrf.fr
Erna Van Wyk
Multimedia Communications Officer
University of Witwatersrand
Johannesburg, South Africa
Tel +27 11 717 4023 or +27 82 399 6574 erna.vanwyk@wits.ac.za
[ | E-mail | Share ]
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Contact: Erna van Wyk erna.vanwyk@wits.ac.za 27-011-717-4023 University of the Witwatersrand
Amphibian and mammal forerunner share 250 million year old burrow
Synchrotron imaging reveals odd couple - 250 million years ago, a mammal forerunner and an amphibian shared a burrow.
Scientists from South Africa, Australia and France have discovered a world first association while scanning a 250 million year old fossilized burrow from the Karoo Basin of South Africa.
The burrow revealed two unrelated vertebrate animals nestled together and fossilized after being trapped by a flash flood event. Facing harsh climatic conditions subsequent to the Permo-Triassic (P-T) mass extinction, the amphibian Broomistega and the mammal forerunner Thrinaxodon cohabited in a burrow.
Scanning shows that the amphibian, which was suffering from broken ribs, crawled into a sleeping mammal's shelter for protection. This research suggests that short periods of dormancy, called aestivation, in addition to burrowing behavior, may have been a crucial adaptation that allowed mammal ancestors to survive the P-T extinction.
The results of this research resulted in a paper entitled Synchrotron reveals Early Triassic odd couple: injured amphibian and aestivating therapsid share burrow and that is published in the scientific journal, PLoS ONE, on Friday, 21 June 2013 at 23:00 SA Standard Time.
The international team of scientists was led by Dr Vincent Fernandez from Wits University, South Africa and the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The other authors from Wits University include Prof. Bruce Rubidge (Director of the newly formed Palaeosciences Centre of Excellence at Wits), Dr Fernando Abdala and Dr Kristian Carlson. Other authors include Dr Della Collins Cook (Indiana University); Dr Adam Yates (Museum of Central Australia) and Dr. Paul Tafforeau (ESRF).
After many impressive results obtained on fossils, synchrotron imaging has led to revived interest in the studies of the numerous fossilized burrows discovered in the Karoo Basin of South Africa and dated to 250 million years ago. The first attempt to investigate one of these burrow-casts surprisingly revealed a world-first association of two unrelated animals.
The fossil was recovered from sedimentary rock strata in the Karoo Basin. It dates from 250 million years ago, at the beginning of the Triassic Period. At that time, the ecosystem was recovering from the Permo-Triassic mass extinction that wiped out most of life on Earth. In the Pangea Supercontinent context, what is now South Africa was an enclave in the southern half called Gondwana. It was the scene of pronounced climatic warming and increased seasonality marked by monsoonal rainfall. To survive this harsh environment, many animals, including mammal-like reptiles (mammal forerunners), developed a digging behavior, attested by the numerous fossilized burrow casts discovered in the Karoo Basin. These casts have long been thought to enclose fossilized remains, triggering interest from palaeontologists. Early this year, an international group of scientists started to research the contents of these burrows using X-ray synchrotron computed microtomography.
Two burrow casts were selected from the collection at Wits to be scanned using the state-of-the-art facility at the European Synchrotron Radiation Facility (ESRF). Using the unique properties of the X-ray beam which enables non-destructive probing, the scan of the first burrow started to reveal the skull of a mammal-like reptile called Thrinaxodon, an animal previously reported in another burrow.
As the scan progressed, the three-dimensional reconstruction displayed results beyond expectations: the mammal-like reptile was accompanied by an amphibian Broomistega, belonging to the extinct group of Temnospondyl.
"While discovering the results we were amazed by the quality of the images", says lead author Fernandez, "but the real excitement came when we discovered a second set of teeth completely different from that of the mammal-like reptile. It was really something else".
Besides the pristine preservation of the two skeletons, the team focused on the reasons explaining such an unusual co-habitation. Fernandez explains: "Burrow-sharing by different species exists in the modern world, but it corresponds to a specific pattern. For example, a small visitor is not going to disturb the host. A large visitor can be accepted by the host if it provides some help, like predator vigilance. But neither of these patterns corresponds to what we have discovered in this fossilized burrow".
The scientists gathered all the information to try to reconstitute the events that led to this incredible fossil aggregation, testing scenarios one after another. "It's a fascinating scientific question: what caused the association of these two organisms in the burrow? One of the more obvious possibilities is a predator-prey interaction, but we inspected both skeletons looking for tooth marks or other evidence implying predation, ultimately finding no support for one having attempted to feed on the other," says Carlson.
His colleague, Cook, adds that the consecutive broken ribs resulted from a single, massive trauma. The amphibian clearly survived the injury for some time because the fractures were healing, but it was surely quite handicapped. According to Fernandez this Broomistega is the first complete skeleton of this rare species that has been discovered. "It tells us that this individual was a juvenile and mostly aquatic at that time of its life," he says.
The scientists eventually concluded that the amphibian crawled into the burrow in response to its poor physical condition but was not evicted by the mammal-like reptile.
Numerous Thrinaxodon specimens have been found in South Africa, many of them fossilized in a curled-up position. Abdala says: "I have always been fascinated by the preservation of Thrinaxodon fossils in a curled-up position that show even tiny bones of the skeleton preserved. It's as if they were peacefully resting in shelters at the time of death".
The shelters prevented disturbance of the skeletal remains from scavengers and weathering. "We also think it might reflect a state of torpor called aestivation in response to aridity and absence of food resources," Abdala says.
Piecing all the clues together, the team finally elucidated the enigmatic association, concluding that "the mammal-like reptile, Thrinaxodon, was most probably aestivating in its burrow, a key adaptation response together with a burrowing behavior which enabled our distant ancestors to survive the most dramatic mass extinction event. This state of torpor explains why the amphibian was not chased out of the burrow," says Rubidge.
Both animals were finally entrapped in the burrow by a sudden flood and preserved together in the sediments for 250 million years.
Tafforeau says: "Thanks to the unique possibilities for high quality imaging of fossils developed during the last decade at the ESRF, these unique specimens remain untouched, protected by their mineral matrix. Who knows what kind of information we'll be able to obtain from them in the future and which would have been completely lost if the specimen had been prepared out of its burrow cast?"
###
TO INTERVIEW WITS RESEARCHERS:
Dr Vincent Fernandez
European Synchrotron Radiation Facility, France
Evolutionary Studies Institute, Wits University
Tel: +33 4 76 88 28 56 or +33 6 95 57 68 96
Email: vincent.fernandez@esrf.fr
Dr Kristian Carlson
Evolutionary Studies Institute, Wits University
Tel +27 (0) 11 717 6681 or +27 (0) 73 666 0106
Email: Kristian.Carlson@wits.ac.za
Prof. Bruce Rubidge
Director for the Centre for Excellence in Palaeosciences as well as the Evolutionary Studies Institute, Wits University
Tel +27 (0) 11 717 6685 or +27 (0) 72 575 7752
Email: Bruce.Rubidge@wits.ac.za
Issued by:
Claus Habfast
ESRF
Grenoble, France
Head of Communication Group
Tel +33 4 7688 2128 or +33 666 662 384 claus.habfast@esrf.fr
Erna Van Wyk
Multimedia Communications Officer
University of Witwatersrand
Johannesburg, South Africa
Tel +27 11 717 4023 or +27 82 399 6574 erna.vanwyk@wits.ac.za
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Public release date: 21-Jun-2013
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