Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




EARLY EARTH
Oddest couple ever found
by Staff Writers
Johannesburg, South Africa (SPX) Jun 25, 2013


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.

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.

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?"

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).

.


Related Links
University of the Witwatersrand
Explore The Early Earth at TerraDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





EARLY EARTH
Putting flesh on the bones of ancient fish
Uppsala, Sweden (SPX) Jun 18, 2013
This week in the journal Science, Swedish and Australian researchers present the miraculously preserved musculature of 380 million year old fossil fishes, revealed by unique fossils from a locality in north-west Australia. The finds will help scientists to understand how neck muscles and abdominal muscles - "abs" - evolved. The word "fossil" naturally conjures up a vision of rattling skele ... read more


EARLY EARTH
Metamorphosis of Moon's Water Ice Explained

Scientists use gravity, topographic data to find unmapped moon craters

Australian team maps Moon's hidden craters

LADEE Arrives at Wallops for Moon Mission

EARLY EARTH
Mars had oxygen-rich atmosphere 4,000 million years ago

Billion-Pixel View of Mars Comes From Curiosity Rover

Study: Mars may have had ancient oxygen-rich atmosphere

Opportunity Recovers From Another Flash-Related Reset

EARLY EARTH
NASA Bill Would 'End Reliance on Russia,' Nix Asteroid Capture Project

Britain shut down UFO desk after finding no threat: files

New Zealand emerges as guinea pig for global tech firms

NASA announces eight new astronauts, half are women

EARLY EARTH
China's Shenzhou-10 spacecraft returns to Earth

Xi vows bigger stride in space exploration

Chinese astronauts manually dock spacecraft

China astronaut teaches lesson from space

EARLY EARTH
Russian cosmonauts conduct space station tasks in spacewalk

Accelerating ISS Science With Upgraded Payload Operations Integration Center

Strange Flames on the ISS

Europe's space truck docks with ISS

EARLY EARTH
New Mexico Space Grant Consortium student experiments blast into space from Spaceport America

Arianespace Soyuz Puts Four O3b Networks' Birds Into Orbit

Four O3b Network birds integrated to Arianespace Soyuz launcher

Arianespace will retain its market leadership by building on the company's flexibility and agility

EARLY EARTH
Retirement for planet-hunting space probe

Trio of 'super Earths' in a star's habitable zone

Study finds planets in habitable zone around a distant star

NASA's Hubble Uncovers Evidence of Farthest Planet Forming From its Star

EARLY EARTH
Laser can identify substances, could be military tool

Disney Research creates techniques for high quality, high resolution stereo panoramas

Cheap, color, holographic video

Crowd-funded videogame console selling fast




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement