Star Wars-style planets with two suns may host life

by phenomenica on June 17, 2013

in Space, Videos

Planets with two suns – like Tatooine in the “Star Wars” movie series – may be more capable of supporting life than other planets, a new research has claimed.

Tatooine’s dual suns might actually help prevent damaging solar winds from bombarding planets in their system, allowing for a wider “Goldilocks zone” of habitability, Joni Clark, an undergraduate at New Mexico State University, said.

He presented his research at the 222nd meeting of the American Astronomical Society in Indianapolis, SPACE.Com reported.

“[The stars] calm each other down,” Clark said, based on her new work that expands on earlier studies examining binaries.

“It’s like a really good marriage. They vent to each other, and they’re not focused on anything else. They slow each other down and that causes increased magnetic protection of the planets,” Clark told the website.

When the stars in a binary are somewhat evenly matched in mass, they can enter into a synchronised dance that keeps solar winds to a minimum.

The stars also need to fully orbit one another within 10 to 30 days to expand the habitable zone. If they drift too far apart, it could put a significant gravitational strain on the orbiting planets.

The magnetic fields of the planets aren’t necessarily boosted in these kinds of binary systems, Clark said, but they don’t have to deal with as much solar assault.

Water worlds and rocky planets could form in areas of the system that might not be habitable without the double star interaction.

“It also leaves the potential open for smaller planets that have less magnetic field protection to remain habitable because in a sense they don’t have to protect themselves from as much as they would in a single star case,” Clark said.

Clark found that some “p-type” planets (that orbit both stars in a binary system) receive 0.7 per cent less flux from solar wind than Earth depending on their position in the solar system.

“Potentially, p-type binaries could have more potential for habitability,” Clark said.

In these systems, it’s also possible that habitable alien planets could exist as close-in to their stars as Venus is to the Sun.

PTI

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Huge earth-passing asteroid identified as ‘entirely new beast’

by phenomenica on June 17, 2013

in Asteroids, Space, Videos

Scientists have discovered that a big asteroid that flew past Earth last month belongs to a new category of space rock, thanks to new radar images captured by the Arecibo Observatory in Puerto Rico.

Asteroid 1998 QE2 and its moon sailed within 3.6 million miles (5.8 million kilometers) of Earth on May 31, making their closest approach to our planet for at least the next two centuries.

Arecibo’s Ellen Howell reveled in a statement that the asteroid is dark, red, and primitive – which means that it hasn’t been heated or melted as much as other asteroids, Discovery News reported.

Howell added that QE2 is an entirely new beast in the menagerie of asteroids near Earth.

The asteriod was discovered in August 1998 by astronomers working with MIT ‘s Lincoln Near Earth Asteroid Research program in New Mexico. The space rock completes one lap around the sun every 3.8 years.

ANI

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Flying dinosaurs roamed England 110 million years ago

by phenomenica on June 14, 2013

in Palaeontology, Prehistory, Science, Videos

A new study has found that a wide variety of flying reptiles were present in England 110 million years ago.

Brazilian paleontologists Taissa Rodrigues, of the Federal University of Espirito Santo, and Alexander W. A. Kellner, of the National Museum of the Federal University of Rio de Janeiro, have just presented the most extensive review yet available of toothed pterosaurs from the Cretaceous of England.

The study features detailed taxonomic information, diagnoses and photographs of 30 species.

Pterosaurs from the Cretaceous of England were first described by British naturalists Richard Owen and Harry Seeley in the 19th century, when little was known about the diversity of the group, resulting in the description of dozens of species, all based on very fragmentary remains, represented mostly by the tips of the snouts of these animals.

However, more recent findings of pterosaur fossils have challenged views on their diversity.

Results show that these pterosaurs had a remarkable diversity in their appearances.

Some species had head crests of different sizes and shapes, while others had none.

Most had large teeth at the tip of their snouts and were fish eaters, but others had smaller teeth, suggesting different feeding preferences.

The paleontologists were able to identify fourteen different species, belonging to at least five different genera, showing a greater diversity than previously thought.

Most of these fossils were found in a deposit known as the Cambridge Greensand, located in the eastern part of the country.

This unit, one of the most important for the study of flying reptiles, records a past marine environment where the bones that were already fossilized and buried, were eroded, exposed to weathering, and then buried again. Cycles of erosion and burial must have taken place during several years.

Due to this peculiarity, the pterosaur assemblage from this deposit probably presents temporal mixing of faunas, thus explaining the high diversity found.

Another find was that these English flying reptiles turned out to be closely related to species unearthed in northeastern Brazil and eastern China.

The findings are published in the open access journal ZooKeys.

ANI

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Speed — and brakes — make the cheetah a champion

by phenomenica on June 14, 2013

in Nature, Science, Videos

Cheetahs are renowned as the fastest things on legs, but just as important as their speed is their ability to brake, enabling them to twist and turn in pursuit of prey, a study published on Wednesday says.

British researchers fitted three female and two male cheetahs in Botswana with special collars equipped with GPS, accelerometers and gyroscopes to track their location and movements.

The animals were released back into the wild and their activities were archived over the next 17 months, notching up a total of 367 hunts.

The top speed recorded during this period was 93 kilometres (58 miles) per hour, just 7 kph (4 mph) off the fastest cheetah ever.

It was nearly double the fastest recorded pace set by a human, which was 43.2 kph (27 mph), once reached by Usain Bolt in a 100m race.

The cheetahs’ average sprint was far lower, though, at 50 kph (31 mph) — and they sustained this pace for only one or two seconds.

Even more impressive was the cheetah’s ability to hit the accelerator and then the brake.

In a single stride, the animal can speed up by up to three metres (10 feet) per second, or choose to slow by up to four metres (13 feet) by second.

This fast-start, sudden-stop ability — almost double that of polo horses — is due to the cheetah’s remarkable skeleton, which is supplemented by limb and back muscles that account for around 45 percent of its body mass.

These are supplemented by ridged footpads and claws that act as cleats, grabbing hold of the ground to provide extra grip for sideways acceleration or deceleration.

“We recorded some of the highest measured values for lateral and forward acceleration, deceleration and bodymass-specific power for any terrestrial mammal,” says the study, led by Alan Wilson of the Structure and Motion Laboratory at the Royal Veterinary College at the University of London.

For all their prowess, the cheetahs still had to work hard for their dinner.

Out of 367 hunts, only 94 — 26 percent — were successful.

AFP

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50 years ago, Valentina Tereshkova became first woman in space

by phenomenica on June 14, 2013

in Space, Videos

On June 16, 1963, Valentina Tereshkova became the first woman to fly into space in a scientific feat that was a major propaganda coup for the Soviet Union.

Two years after Yuri Gagarin’s historic first manned flight, Tereshkova blasted off in a Vostok-6 spaceship, becoming a national heroine at the age of 26.

She remains the only woman ever to have made a solo space flight.

In April 1962, officials narrowed down the candidates for the flight to five. In a top-secret process, they picked two engineers, one school teacher, one typist and one factory worker who had performed 90 parachute jumps: this was Tereshkova.

After seven months of intensive training, they chose Tereshkova, who grew up in a peasant family and was a Communist Youth (Komsomol) leader at her textile factory in the historic city of Yaroslavl, around 280 kilometres from Moscow.

Tereshkova was not allowed to confide even in family members, who only learnt of her exploit when Moscow announced it to the entire world.

When she blasted off from the Baikonur cosmodrome in Kazakhstan, another Soviet spaceship, Vostok-5, was already in orbit for two days, piloted by cosmonaut Valery Bykovsky.

During her three-day mission, Tereshkova circled Earth 48 times. On the first day, she communicated with Bykovsky and even sang him songs. Their communication was then interrupted as the two spaceships moved further away from each other.

Her flight experienced numerous glitches which were only made public after the fall of the Soviet Union.

“A problem appeared on the first day of the flight,” Tereshkova said at a press conference in Star City, home to a cosmonaut training centre, earlier this month.

“Due to a technical error, the spaceship was programmed not for a landing but for taking the ship into a higher orbit,” she said, meaning that the ship was heading further and further from Earth.

The error was corrected, but chief constructor Sergei Korolyov asked Tereshkova not to tell anyone.

“I kept the secret for 30 years,” she said.

Tereshkova wrote in her official report that her spacesuit hurt her leg and that her helmet weighed down her shoulders and scratched her head. She also said she vomited during the flight.

This information was also kept under wraps in order not to spoil the triumph of the first woman in space.

AFP

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Saturn’s icy moon Dione had a watery past?

by phenomenica on June 12, 2013

in Saturn, Solar System, Space

New images from NASA’s Cassini spacecraft show that the plain-looking Saturn moon Dione may have once had a geologically active subsurface ocean.

Images of Dione’s 500-mile-long (800 kilometers) mountain Janiculum Dorsa suggest that the moon could have been a weaker copycat of Enceladus, Saturn’s icy geyser moon.

“There may turn out to be many more active worlds with water out there than we previously thought,” Bonnie Buratti, who leads the Cassini science team at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement.

Subsurface oceans are thought to exist on several bodies in the solar system, including Saturn’s moons Enceladus and Titan and Jupiter’s moon Europa.

These geologic hotspots have garnered the interest of scientists searching for the building blocks of life beyond Earth.

If Dione turned out to have a liquid layer under its crust, that would increase the moon’s chances of supporting life.

dione

Janiculum Dorsa, a mountain range on Saturn’s moon Dione, as revealed by the satellite Cassini. Color denotes elevation, with red as the highest area and blue as the lowest. The crust under the mountain range has warped, suggesting that Dione’s icy crust was sliding atop a warmer icy layer on top of a liquid water ocean, when the mountain formed. Image credit: NASA/JPL-Caltech/SSI/Brown

Cassini, which has been exploring Saturn since 2004, detected a weak particle stream coming from Dione with its magnetometer.

Images taken by the spacecraft suggest a slushy liquid layer might exist beneath its icy crust, as well as ancient, inactive fractures that now spew water ice and carbon-containing particles, much like ones seen on Enceladus.

Dione’s Janiculum Dorsa ranges from about 0.6 to 1.2 miles (1 to 2 kilometers) in height. The mountain seems to have deformed the icy crust underneath by as much as 0.3 mile (0.5 kilometer).

The deformation implies the crust was warm, most likely from a subsurface ocean when the mountain formed, the researchers said.

The findings are published in the journal Icarus.

ANI

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Martian clay contains chemical implicated in origin of life

by phenomenica on June 11, 2013

in Extraterrestrial Life, Mars, Solar System, Space

Researchers from the University of Hawaii at Manoa NASA Astrobiology Institute (UHNAI) have discovered high concentrations of boron in a Martian meteorite.

When present in its oxidized form (borate), boron may have played a key role in the formation of RNA, one of the building blocks for life.

The Antarctic Search for Meteorites team found the Martian meteorite used in this study in Antarctica during its 2009-2010 field season. The minerals it contains, as well as its chemical composition, clearly show that it is of Martian origin.

Using the ion microprobe in the W. M. Keck Cosmochemistry Laboratory at UH, the team was able to analyze veins of Martian clay in the meteorite. After ruling out contamination from Earth, they determined boron abundances in these clays are over ten times higher than in any previously measured meteorite.

“Borates may have been important for the origin of life on Earth because they can stabilize ribose, a crucial component of RNA. In early life RNA is thought to have been the informational precursor to DNA,” said James Stephenson, a UHNAI postdoctoral fellow.

mars-look-marineris-volcano-deskRNA may have been the first molecule to store information and pass it on to the next generation, a mechanism crucial for evolution. Although life has now evolved a sophisticated mechanism to synthesize RNA, the first RNA molecules must have been made without such help.

One of the most difficult steps in making RNA nonbiologically is the formation of the RNA sugar component, ribose. Previous laboratory tests have shown that without borate the chemicals available on the early Earth fail to build ribose. However, in the presence of borate, ribose is spontaneously produced and stabilized.

On our planet, borate-enriched salt, sediment and clay deposits are relatively common, but such deposits had never previously been found on an extraterrestrial body. This new research suggests that when life was getting started on Earth, borate could also have been concentrated in deposits on Mars.

The presence of ancient borate-enriched clays on Mars implies that these clays may also have been present on the early Earth. Borate-enriched clays such as the one studied here may have represented chemical havens in which one of life’s key molecular building blocks could form.

The work was published on June 6 in PLOS One.

ANI

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Planktons found in 3 billion-year-old microfossils

by phenomenica on June 11, 2013

in Palaeontology, Prehistory, Science

Researchers have revealed that the spindle-shaped inclusions in 3 billion-year-old rocks are microfossils of plankton that probably inhabited the oceans around the globe during that time.

“It is surprising to have large, potentially complex fossils that far back,” Christopher H. House, professor of geosciences, Penn State, and lead author, said.

However, the researchers not only showed that these inclusions in the rocks were biological in origin, but also that they were likely planktonic autotrophs-free-floating, tiny ocean organisms that produce energy from their environment.

The researchers looked at marine sediment rocks from the Farrel Quartzite in Western Australia.

Isotopic analysis using secondary ion mass spectrometry was carried out at UCLA.

“Ken (Kenichiro Sugitani, professor, Graduate School of Environmental Studies, Nagoya University, Japan, and a co-author) discovered these unusually shaped microfossils embedded in really old rock,” House said.

plankton

Spindle-like microstructures from the Farrel Quartzite, Western Australia.
Image credit: Christopher H. House

To determine if these inclusions were actually biological in origin, the researchers looked at 15 different samples of Farrel Quartzite and determined their stable carbon isotope ratios.

The percentage of carbon 13 in the microfossils was indicative of material produced by biological processes.

They found that the carbon 13 percentage in the background organic matter in the surrounding rock was different from that of the microstructures.

“When considered along with published morphological and chemical studies, these results indicate that the Farrel Quartzite microstructures are bona fide microfossils, and support the interpretation that the spindles were planktonic,” the researchers said.

The spindle-shaped microfossils are from 20 to 60 microns in length, about the size of fine sand and within the size range of today’s micro plankton.

The findings are published in the journal Geology.

ANI

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Future humans to look like Pokemon characters?

by phenomenica on June 11, 2013

in Science

Humans may look like Pokemon characters, 100,000 years from now, sporting larger heads, bigger eyes and improved night vision, researchers believe.

Two researchers claim that humans in the future may have larger heads, Google Glass type contact lenses and sideways-blinking oversized Disney eyes that glow green with cat-like night vision.

“This is speculation based on reason,” artist Nickolay Lamm said.

“When I designed it I wasn’t thinking of anime, but I can see the resemblance. It’s kind of a coincidence that happened,” he said.

Lamm collaborated with computational geneticist Alan Kwan to envision a future where zygotic genome engineering technology develops to the point where humans will be able to control their own evolution the way we control electrons today.

“In this future, humankind has wrested control of the human form from natural evolution and are able to bend human biology to human needs,” Kwan said.

poke

Image credit: Nickolay Lamm/MyVoucherCodes.co.uk

This ability, could result in more facial features that humans find intrinsically attractive: strong lines, straight nose, intense eyes and perfect symmetry. But other changes will be driven by function, the researchers suggest.

Kwan thinks that the human head might expand to accommodate a larger brain as our knowledge of the universe increases. This future human would appear to have a “subtly too large” forehead.

They also believe that millennia of space colonisation could also produce larger eyes to account for dimmer environments when humans live farther from the sun and darker skin in general to protect against UV radiation beyond the Earth’s ozone.

Thicker eyelids and a more prominent superciliary arch, the bone above the eye socket, could offset the same kind of disorientation that today’s astronauts sometimes feel aboard the International Space Station, they added.

Perhaps their most remarkable conjecture is that future humans could start to blink sideways like owls to “protect from cosmic ray effects,” the researchers added.

However, Kwan and Lamm insist that their experiment was always intended to be more existential than scientific.

“I just tried to do this for fun. This project was more for entertainment purposes,” Lamm said.

PTI

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120,000-year-old Neanderthal rib shows sign of bone tumor

by phenomenica on June 6, 2013

in Palaeontology, Prehistory, Science

The first case of a bone tumor of the ribs in a Neanderthal specimen reveals that at least one Neanderthal suffered a cancer that is common in modern-day humans, according to a new research.

This discovery by David Frayer from the University of Kansas and colleagues of a fibrous dysplasia predates previous evidence of this tumor by well over 100,000 years.

Prior to this research, the earliest known bone cancers occurred in samples approximately 1000-4000 years old.

The cancerous rib, recovered from Krapina in present-day Croatia is an incomplete specimen, and thus the researchers were unable to comment on the overall health effects the tumor may have had on this individual.

Fibrous dysplasia in modern-day humans occurs more frequently than other bone tumors, but Frayer says that, “Evidence for cancer is extremely rare in the human fossil record. This case shows that Neanderthals, living in an unpolluted environment, were susceptible to the same kind of cancer as living humans.”

ribs

A Neanderthal rib fragment.
Image credit: L. Mjeda

Neanderthals had average life spans that were likely to be half those of modern humans in developed countries, and were exposed to different environmental factors.

The study concludes, “Given these factors, cases of neoplastic disease are rare in prehistoric human populations. Against this background, the identification of a more than 120,000-year-old Neanderthal rib with a bone tumor is surprising, and provides insights into the nature and history of the association of humans to neoplastic disease.”

The findings are published in the open access journal PLOS ONE.

ANI

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Is Armstrong’s famous Moon-landing quote really a misquote?

by phenomenica on June 6, 2013

in Space

Historic misquote? Neil Armstrong’s famous quote “That’s one small step for man, one giant leap for mankind” uttered by the American astronaut after becoming the first person to land on the Moon in 1969 had a small error, according to a new study.

A team of researchers from Michigan State University and Ohio State University has taken a second listen to Armstrong’s famous quote and may have provided evidence that he did indeed say the word “a” as part of that famous saying.

When he took his first step on the moon, Armstrong claimed he said, “That’s one small step for a man, one giant leap for mankind.” However, many listeners think he left out the “a”.

As the American astronaut himself pointed out many times, the sentence is meaningful only if he says, “That’s one small step for a man.”

Armstrong claimed that is what he said on July 20, 1969 as he lowered his foot from the lunar module to the surface of the Moon, otherwise, there is no distinction between a single individual and all of humanity.

But now the researchers have taken a novel approach to deciphering Armstrong’s quote by studying how speakers from his native central Ohio pronounce “for” and “for a.” Their results suggest that it is entirely possible that Armstrong said what he claimed, though evidence indicates that people are statistically more likely to hear “for man” instead of “for a man” on the recording.

Armstrong was raised in central Ohio, where there is typically a lot of blending between words such as “for” and “a”, according to a Michigan State University (MSU) statement.

“Prior acoustic analyses of Neil Armstrong’s recording have established well that if the word ‘a’ was spoken, it was very short and was fully blended acoustically with the preceding word,” said Laura Dilley, an MSU assistant professor of communicative sciences and disorders and part of the research team.

If Armstrong actually did say “a,” she said, it sounded something like “frrr(uh).” His blending of the two words, compounded with the poor sound quality of the transmission, has made it difficult for people to corroborate his claim that the “a” is there.

Dilley and her colleagues thought they might be able to figure out what Armstrong said with a statistical analysis of the duration of the “r” sound as spoken by native central Ohioans saying “for” and “for a” in natural conversation.

They used a collection of recordings of conversational speech from 40 people raised in Columbus, Ohio, near Armstrong’s native town of Wapakoneta. Within this body of recordings, they found 191 cases of “for a.”

They matched each of these to an instance of “for” as said by the same speaker and compared the relative duration. They also examined the duration of Armstrong’s “for (a)” from the lunar transmission.

The researchers found a large overlap between the relative duration of the “r” sound in “for” and “for a” using the Ohio speech data.

“We’ve bolstered Neil Armstrong’s side of the story,” she said. “We feel we’ve partially vindicated him. But we’ll most likely never know for sure exactly what he said based on the acoustic information.”

PTI

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Astronomers spot lightest exoplanet

by phenomenica on June 5, 2013

in Space, Videos

Astronomers may have discovered the lightest exoplanet ever seen, which appears just as a dot orbiting a young star.

The newly discovered planet orbits the young star HD 95086 at a distance of around 56 times the distance from the Earth to the Sun, twice the Sun’Neptune distance.

Although nearly a thousand exoplanets have been detected indirectly, most using the radial velocity or transit methods and many more candidates await confirmation, only a dozen exoplanets have been directly imaged.

ESO’s Very Large Telescope captured on camera what is probably the lightest of these objects so far.

“Direct imaging of planets is an extremely challenging technique that requires the most advanced instruments, whether ground-based or in space,” says Julien Rameau from Institut de Planetologie et d’Astrophysique de Grenoble, France.

“Only a few planets have been directly observed so far, making every single discovery an important milestone on the road to understanding giant planets and how they form,” said Rameau.

The likely planet appears as a faint but clear dot close to the star HD 95086. A later observation also showed that it was slowly moving along with the star across the sky.

This suggests that the object, which has been designated HD 95086 b, is in orbit around the star. Its brightness also indicates that it has a predicted mass of only four to five times that of Jupiter.

The observations were made using infrared light and a technique called differential imaging, which improves the contrast between the planet and dazzling host star.

The star itself is a little more massive than the Sun and is surrounded by a debris disc. These properties allowed astronomers to identify it as an ideal candidate to harbour young massive planets. The whole system lies some 300 light-years away from us.

The youth of this star, just 10 to 17 million years, leads astronomers to believe that this new planet probably formed within the gaseous and dusty disc that surrounds the star.

“Its current location raises questions about its formation process. It either grew by assembling the rocks that form the solid core and then slowly accumulated gas from the environment to form the heavy atmosphere, or started forming from a gaseous clump that arose from gravitational instabilities in the disc,” said researcher Anne-Marie Lagrange.

“Interactions between the planet and the disc itself or with other planets may have also moved the planet from where it was born,” said Lagrange.

PTI

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Dinosaurs possibly the earliest animals to get toothache

by phenomenica on June 5, 2013

in Palaeontology, Prehistory

Scientists from China, the US and Canada found the fossilised jawbone of Sinosaurus, presumed to have existed 190 million years ago, and concluded that it could be the earliest discovered animal that had a toothache.

The scientists held a dental consultation on the dinosaur, taking X-rays and writing a report on its toothache, which was published in Chinese Science Bulletin last week.

The extinct animal earlier could have developed a toothache after biting into something hard that it damaged its gum, according to the study.

“It was common for carnivorous dinosaurs to lose teeth, but this specimen we were studying was different,” Xing LiDa, who co-authored the research report.

“Its tooth socket was completely filled, which indicates the tooth loss was because of dental problems instead of external force,” Xing told state-run China Daily here today.

In 2007, the Lufeng Dinosaurian Museum recovered an incomplete skull and several postcranial fragments of a new specimen of Sinosaurus from Lufeng Basin in Yunnan province.

sinosaurus-triassicus-art-990x692

Image credit: Wikimedia

Based on other Sinosaurus specimens, the complete upper jaw should have 13 or 14 tooth positions.

The skeleton had two broken teeth preserved in the tooth socket.

An X-ray of the bone shows the outline of the original tooth socket.

The space of the bad tooth is less radiolucent than the adjacent tooth socket – in other words, X-rays don’t pass through as much – which indicates that secondary bone filled the space, the report said.

“When the dinosaur’s teeth were lost or removed while it was alive, the bony socket remodelled over time, so that there was no longer a tooth socket,” Xing said.

Scientists also found no pyrite rot in the socket of the bad tooth, while pyrite growth was observed over all the other tooth spaces.

“The osseous abnormalities after teeth loss is common among mammals, but it is rarely found on reptiles like the dinosaur,” professor Bruce M Rothschild, at the University of Kansas Natural History Museum and Biodiversity Research Institute said, in a news release about the research report, which he also co-authored.

Canadian paleontologist Phil R Bell compared the Sinosaurus jawbone to a skeleton of a ring-tailed lemur because the ring-tailed lemur likes chewing hard nuts, which causes teeth problems similar to those of the Sinosaurus.

“The dinosaur might have hurt its teeth and got the teeth problem for similar reasons,” Bell said in the news release.

“The study of disease and other abnormalities in the fossil record can reveal unique insights into the behaviour, biology and development of extinct animals.

“For example, among theropod dinosaurs, injury-related trauma like bites, exostoses, fractures, infection and stress fractures are the overriding cause of osteopathy,” he said.

PTI

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Human ancestors changed diet 3.5 million years ago

by phenomenica on June 5, 2013

in Prehistory, Science, Videos

Human ancestors expanded their menu 3.5 million years ago, adding tropical grasses and sedges to an ape-like diet and setting the stage for our modern diet of grains, grasses, and meat and dairy from grazing animals, new research has claimed.

In four new studies of carbon isotopes in fossilised tooth enamel from scores of human ancestors and baboons in Africa from 4 million to 10,000 years ago, a team of two dozen researchers found a surprise increase in the consumption of grasses and sedges – plants that resemble grasses and rushes but have stems and triangular cross sections.

“At last, we have a look at 4 million years of the dietary evolution of humans and their ancestors,” said University of Utah geochemist Thure Cerling, principal author of two of the four new studies published in the journal Proceedings of the National Academy of Sciences.

“For a long time, primates stuck by the old restaurants – leaves and fruits – and by 3.5 million years ago, they started exploring new diet possibilities – tropical grasses and sedges – that grazing animals discovered a long time before, about 10 million years ago when African savanna began expanding,” Cerling said.

Grassy savannas and grassy woodlands in East Africa were widespread by 6 million to 7 million years ago. It is a major question why human ancestors didn’t seriously start exploiting savanna grasses until less than 4 million years ago.

Direct evidence of human ancestors scavenging meat doesn’t appear until 2.5 million years ago, and definitive evidence of hunting dates to only about 5,00,000 years ago.

“The earliest human ancestor to consume substantial amounts of grassy foods from dry, more open savannas may signal a major and ecological and adaptive divergence from the last common ancestor we shared with African great apes, which occupy closed, wooded habitats,” said University of South Florida geologist Jonathan Wynn, chief author of one of the new studies and a former University of Utah master’s student.

“Diet has long been implicated as a driving force in human evolution,” said Matt Sponheimer, a University of Colorado, Boulder anthropologist, former University of Utah postdoctoral fellow and lead author of the fourth study.

Sponheimer noted that changes in diet have been linked to both larger brain size and the advent of upright walking in human ancestors roughly 4 million years ago.

If diet has anything to do with the evolution of larger brain size and intelligence, then we are considering a diet that is very different than we were thinking about 15 years ago, when it was believed human ancestors ate mostly leaves and fruits, Cerling added.

PTI

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20 mn-year-old extinct koala species discovered

by phenomenica on June 3, 2013

in Palaeontology, Prehistory

Scientists have discovered an extinct species of koala bear that lived in the rainforest canopies of northern Australia about 20 million years ago.

The discovery was made after an exceptionally well-preserved partial skull of the new extinct species was unearthed from the Riversleigh World Heritage Area, whereas only teeth or jaws of most other extinct koala species have been found.

The small, ancient koala was given the species name Litokoala dicksmithi, in honour of a famous Australian aviator, adventurer and philanthropist Dick Smith.

“We chose the name to thank Mr Smith for his long-term financial support of Australian science, in particular, of fossil research at the Riversleigh World Heritage Area in north western Queensland,” said Dr Karen Black, University of New South Wales (UNSW) paleontologist, who led the research.

Black, along with Dr Julien Louys and Dr Gilbert Price from the University of Queensland, described the new species in the Journal of Systematic Palaeontology.

The discovery brings the number of known extinct koala species to 18. Today, only one species of koala is alive.

koala

Litokoala dicksmithi skull. Image credit: UNSW

“The discovery of Litokoala dicksmithi is particularly significant because it is one of only two fossil koala species that are known from material preserving the facial region including the snout,” Black said.

“The other species, called Nimiokoala greystanesi, which was also discovered at Riversleigh, had a skull that was very possum-like in appearance.

“Litokoala dicksmithi, however, appears to have been much more closely related to the modern koala with numerous similarities in the skull suggesting a more koala-like, rather than possum-like, face,” Black said.

Litokoala dicksmithi was only about a third of the size of living koalas, weighing in at approximately three to four kilogrammes.

“An interesting feature of the Litokoala skull is the extremely large eye sockets which suggest the intriguing possibility that these koalas were nocturnal with greater visual acuity than the living koala,” Black said.

“Combined with its small body size, this suggests that Litokoala dicksmithi was a more active, agile tree climber than its sleepy, relatively sedentary, cousin that we know,” Black said.

Unlike today’s eucalypt-munching koala species, Litokoala dicksmithi fed on the rainforest plants that covered much of northern Australia 20 million years ago and may also have eaten some fruit.

The onset of dryer conditions in Australia about 15 million years ago led to the contraction of rainforest habitats and the apparent extinction of many koala species including Litokoala dicksmithi.

PTI

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