Nests of Big-Clawed Dinosaurs Found in Mongolia

A nursery of bizarre-looking dinosaurs known as therizinosaurs has been found in the Gobi Desert in Mongolia.

The nesting colony contained at least 17 clutches of eggs.

"Not only is this the largest colony of nonavian theropods, but this is the best documented site," said study co-author Yoshitsugu Kobayashi, a vertebrate paleontologist at Hokkaido University in Japan, who presented the findings here at the 73rd annual Society of Vertebrate Paleontology conference.

The finding suggests the odd little creatures were social animals.

Oddball dinos

Therizinosaurs, which lived about 70 million years ago, sported huge, round guts; stumpy legs; a long neck; and a turtlelike head and beak.

Despite being members of the carnivorous group known as theropods — which includes the deadly king of the predators Tyrannosaurus rex — the waddling dinosaurs were herbivores. They also had enormous Edward Scissorhands-like, three-digit claws that may have been used to grasp branches and scrape up plant material, similar to the way bamboo-eating pandas do today.

Kobayashi and his colleagues discovered the nest while in southeastern Mongolia in 2011. On the last day of their trip, they decided to leave the area they were excavating known for therizinosaur bones to instead examine another bone bed nearby.

"There aren't many bones from this formation, so we didn't expect to find anything good," Kobayashi told LiveScience.

As the sun was setting, a guide pointed out an eggshell, and the team soon found one nest site right next to their car. Further investigation revealed four more nest sites. The following year, they returned and excavated a total of 17 clutches, for a total of about 75 eggs.

Hatched youngsters

The eggs were round, with about a 5-inch (13 centimeters) diameter and rough outer shells. Based on size analysis and the species found in nearby areas, the team concluded that therizinosaurs laid the eggs. The animals would have been about 220 lbs. (99 kilograms) when full-grown.

None of the eggs harbored dinosaur embryos. However, many of them had holes with eggshells inside, as if a baby dinosaur had poked a hole in the top of the egg and the broken shells had fallen back inside. The presence of eggshells inside the eggs suggested that most of the baby dinosaurs had hatched.

That finding, in turn, indicated the adults must have guarded the eggs to protect them from predators, Kobayashi said.

Communal animals

The finding bolsters the notion that therizinosaurs were social animals that hung out together.

"We have some very intriguing evidence of mass congregation in therizinosaurs," said Lindsay Zanno, director of the paleontology and geology research laboratory at the North Carolina Museum of Natural Sciences.

Read more at Discovery News

New World's Oldest Tomatillo Discovered

A fossilized tomatillo, still in its papery shell, is the earliest fruit from the tomato family ever found in South America, researchers reported Oct. 30 at the Geological Society of America's annual meeting in Denver.

The 52.2-million-year-old tomatillo was discovered at the fossil-rich Laguna del Hunco, Argentina, where ancient lakebeds interlayer with volcanic ashes, providing paleontologists with precisely dated discoveries. (Minerals in the ash pin down the rock ages.)

"It's quite amazing," said Peter Wilf, a paleobotanist at Penn State University. "We've collected over 10,000 fossils and there's only one of these."

Though flattened, the ancient fruit (scientific name Physalis) looks remarkably like a modern version of the popular salsa ingredient. The fossil has a dark fruit enclosed by a ribbed calyx (a papery husk) just like modern Physalis, Wilf said. Both the fossil tomatillo and today's plants have husks with five major and five minor ribs, he added. The fossil is nearly an inch (23 millimeters) wide.

Tomatillos are members of the Solanaceae (nightshade) family, which includes tomatoes, potatoes and eggplants. Both fossil and genetic evidence suggests that Solanaceae plants originated and diversified in South America.

But until now, only fossil seeds attributed to Solanaceae plants have been discovered in South America — most of the family's early fossil history comes from Europe. The earliest South American tomato fossil larger than a seed is about 16 million years old.

"This is the first fossil anybody has ever seen of the entire tomato-potato-eggplant family," Wilf said. "It's also pretty old. This actually does match up pretty well with the idea that the Solanaceae family first diversified in South America."

The discovery also pushes back the evolutionary history of the tomato family.

Scientists sequenced the tomato genome in May 2012. The tomato family molecular clock, based on the genetic data and fossil evidence, suggests the tomato genome expanded abruptly about 60 million years ago. A molecular clock estimates when species diverged in the past.

Now, thanks to the tomatillo find, the Solanaceae molecular clock is too young, Wilf said. During his talk, he listed 11 fossils from Laguna del Hunco, such as cycads, trees and the tomatillo, that show their molecular clocks are too young.

"Almost all of the molecular ages are younger than the fossils," Wilf said.

Read more at Discovery News

Oldest Air on Earth Hiding in Antarctic Ice

Tiny puffs of air from 1.5 million years ago may be locked inside bubbles in the ice nearly two miles beneath Antarctica’s surface. That ancient air, if it exists, would be the oldest sample of Earth’s atmosphere ever recovered.

Geoscientists recently identified regions of the frozen continent that potentially preserved the not-so-fresh air. Getting a whiff of the Earth’s oldest breeze would allow an analysis of chemicals in the air at a crucial point from 1.2 million to 900,000 years ago, known as the  Mid-Pleistocene Transition.

“The Mid Pleistocene Transition is a most important and enigmatic time interval in the more recent climate history of our planet,” said lead author of the new study published in Climate of the Past Hubertus Fischer of the University of Bern, Switzerland, in a press release.

During the transition, the Earth went from extreme warmth and cooling cycles alternating  approximately every 41,000 years to having the cycles change only about every 100,000 years. Sediment samples drilled from the bottom of the ocean recorded the temperature differences, but scientists don’t know why the global thermostat cycles slowed.

Ice samples from other areas yielded 800,000-year-old air bubbles. Those samples showed a lockstep correlation between higher greenhouse gas levels and increased temperatures over thousands of years, according to research published in Nature.

Greenhouse gases, such as methane and carbon dioxide, may have been the culprits behind the Mid-Pleistocene Transition, as well. However, drills will need to pluck a 2.4 – 3.2 (1.5 – 2 mile)-kilometer-long ice core from the Antarctic ice to give scientists the 1.5 million-year-old sample they need.

Read more at Discovery News

Hubble Gets Personal With Nearest Stellar Neighbor

When we’re usually more accustomed to seeing distant stars, nebulae and galaxies through the lens of the Hubble Space Telescope, it may come as a surprise that even the sun’s nearest neighbor, Proxima Centauri, is still just a point of light in the great expanse of space. But the red dwarf star, located in the constellation of Centaurus, is over 4.2 light-years away — a short hop by interstellar proportions; still a marathon by anyone’s measure.

Red dwarf stars are curious objects. They’re small and dim, but have the habit of erupting in a flaring temper tantrum. In the case of Proxima, the star is not visible by the naked eye despite its relatively close proximity to our solar system. Proxima is known to undergo dramatic changes in brightness and is therefore a known “flare star.”

Exoplanet hunters have shown interest in hunting for small worlds in “habitable” orbits around red dwarfs as current exoplanet-hunting techniques favor the detection of worlds orbiting close to their host stars. As they output less energy than larger mass stars, red dwarfs’ habitable zones — the region surrounding a star where it’s neither too nor or too cold for liquid water to exist on a rocky planet’s surface — are much closer to the stars’ surface than, say, sun-like stars.

So long as any hypothetical extraterrestrial life in a red dwarf system has a high tolerance for the occasional eruption, red dwarfs could be touted as a good target for future exoplanet-hunting telescopes.

Another interesting fact about red dwarfs, that could boost their life-giving potential, is their longevity. According to a NASA/Hubble news release, “astronomers predict that (Proxima) will remain middle-aged — or a “main sequence” star in astronomical terms — for another four trillion years, some 300 times the age of the current Universe.” (Emphasis added.)

Considering our sun will reach the end of its life within approximately 5 billion years (and fry all life on Earth in less than half that time), stars like Proxima Centauri appear to be a better match for the evolution of life, perhaps nurturing lifeforms for tens, hundreds or even thousands of billions of years.

Read more at Discovery News

Extinct 'Megamouth' Shark Species Identified

Scientists have finally identified a new species of megamouth shark that prowled the oceans about 23 million years ago, nearly 50 years after the first teeth were discovered and then forgotten.

The ancient shark likely prowled both deep and shallow waters for plankton and fish, using its massive mouth to filter food.

"It was a species that was known to be a new species for a long time," said study co-author Kenshu Shimada, a paleobiologist at DePaul University in Chicago. "But no one had taken a serious look at it," said Shimada, who described the new species here at the 73rd annual meeting of the Society for Vertebrate Paleontology.

Shark teeth

Scientists first found shark teeth from the species in the 1960s, but at the time, there were no similar living creatures, so scientists didn't quite know what to make of the find. Over time, researchers turned up hundreds of similar teeth along the coast of California and Oregon. All the specimens were tossed in a drawer and forgotten in the collections of the Los Angeles County Museum and a few other California museums.

Then in 1976, scientists discovered the modern megamouth shark, dubbed Megachasma pelagios, which feeds exclusively on shrimplike creatures called plankton. The sharks use their mammoth mouths to engulf plankton-filled water, forcing the water through gills equipped with a filtering apparatus called gill rakers, which direct plankton into the digestive track.

The monster beast is also a vertical migrator, meaning the shark lurks in the deep ocean during the day, but comes up to the shallow surface waters chasing plankton swarms at night, Shimada said.

Revisiting a shark

When Shimada came across the shark teeth at the Los Angeles County Museum, he was told that other scientists were studying them. But it turned out those scientists weren't actively working on the species.

Shimada contacted those scientists, Douglas Long of the California Academy of Sciences and Bruce Welton of the New Mexico Museum of Natural History, and persuaded them to take a second look with him.

The team found the ancient creature was related to M. pelagios. But unlike the modern shark, it had slightly longer, pointier teeth.

"That suggests that they probably had a wider food selection," Shimada told LiveScience. "They could have probably eaten plankton, but they were also probably feeding on fish."

The team determined the ancient creature would've sported a slightly longer, less-wide snout than the modern megamouth shark. The extinct creature also likely grew to an average of 20 feet (6 meters), but the biggest megamouth individuals might have been nearly 27 feet (8 m) long, not much different from their modern relatives.

Because the teeth were found in both deep-ocean and near-shore marine sediments, the extinct monster probably had already begun to migrate between the deep and shallow oceans in search of food.

Read more at Discovery News

Newly Discovered Giant Platypus Rewrites History

Platypuses existed as oddities since near the end of the age of dinosaurs when Steropodon, the first platypus-like species, appeared in ancient Australia’s fossils. Paleontologists once believed the anomalous animals evolved solo, with only one platypus species living on Earth at a time.

However, a newly discovered extinct 3-foot-long platypus suggests multiple species of the mixed-up mammals swam ancient Australian waters at the same time.

“Discovery of this new species was a shock to us because prior to this, the fossil record suggested that the evolutionary tree of platypuses was relatively linear one,” said Michael Archer of the University of New South Wales, a co-author of the study that described the giant platypus in the Journal of Vertebrate Paleontology, in a press release. “Now we realize that there were unanticipated side branches on this tree, some of which became gigantic.”

All that remains of the giant platypus, named Obdurodon tharalkooschild, is a single tooth. The tooth dates to between five and 15 million years ago. Like much of the rest of the playtpus, the tooth was unique enough to identify the creature and hint at its lifestyle.

“Like other platypuses, it was probably a mostly aquatic mammal, and would have lived in and around the freshwater pools in the forests that covered the Riversleigh area millions of years ago,” said co-author Suzanne Hand of the University of New South Wales in a press release. “Obdurodon tharalkooschild was a very large platypus with well-developed teeth, and we think it probably fed not only on crayfish and other freshwater crustaceans, but also on small vertebrates including the lungfish, frogs, and small turtles that are preserved with it in the Two Tree Site fossil deposit.”

Platypuses’ bodies feature a bizarre grab-bag of biology. Platypuses eat with rubbery-bills that can sense electromagnetic energy fields. Their body temperature only reaches 90 degrees Fahrenheit.  They waddle on land on their knuckles, like gorillas, with their legs splayed like lizards. The animals swim using a hairy, beaver-like tail packed with fat to help them survive starvation. Platypuses’ ear openings lie beneath their jaws. The males sport venomous spikes on their elbows. Females lay eggs, instead of giving birth.

Read more at Discovery News

Weird Forests Once Sprouted in Antarctica

Strange forests with some features of today's tropical trees once grew in Antarctica, new research finds.

Some 250 million years ago, during the late Permian and early Triassic, the world was a greenhouse, much hotter than it is today. Forests carpeted a non-icy Antarctic. But Antarctica was still at a high latitude, meaning that just as today, the land is bathed in round-the-clock darkness during winter and 24/7 light in the summer.

The question, said Patricia Ryberg, a postdoctoral researcher at the University of Kansas Biodiversity Institute, is how plants coped with photosynthesizing constantly for part of the year and then not at all when the winter sun set.

"The trees are the best way to figure this out, because trees record physiological responses" in their rings, Ryberg told LiveScience.

A forest mystery

Fossilized wood and leaf impressions record a history of the Antarctic forests. The leaf impressions appear to show mats of leaves, as if the trees had all shed at once — a sign of a deciduous forest.

To confirm this, Ryberg and her colleagues gathered samples of fossil wood and examined the tree rings. Wood cells in the rings reveal how the trees grew: Early wood is produced when the tree is growing upward and outward. Late wood is produced when the tree is preparing to go dormant. At that point, the tree stops growing and starts storing carbon in its cells. Late wood is denser than early wood, and has thicker cell walls.

Deciduous and evergreen trees have different patterns of late and early wood. Ryberg and her colleagues examined the Antarctic fossils and found that they looked evergreen.

"Now we have leaves that suggest a deciduous habit and fossil wood that is suggesting an evergreen habit, so we have a bit of a contradiction going on," Ryberg said here Wednesday (Oct. 30) at the annual meeting of the Geological Society of America.

Mixed results

Follow-up studies analyzing carbon molecules in the fossil wood also gives both deciduous and evergreen answers, Ryberg said. The implication is that ancient Antarctic forests may have been a mix of deciduous and evergreen.

"It's not one or the other," she said. "It's actually both."

Much of the ring structure looks tropical, Ryberg added. Tropical trees that are not exposed to seasons experience a sort of short-term dormancy that echoes what is seen in the Antarctic wood.

"But they weren't growing in the tropics, so obviously it's two different environmental characteristics," Ryberg said.

Read more at Discovery News

Galaxy Hosts 10 Billion 'Habitable' Earth-Size Worlds

Four years ago, NASA launched the Kepler space telescope to find out how many stars like the sun host Earth-sized planets suitably positioned for liquid water, a key ingredient for life.

On Monday, a team of scientists announced an answer: about 10 billion -- enough for one planet for every person in the world, with 3 billion to spare.

“We didn’t know what to expect,” astronomer Geoffrey Marcy, with the University of California at Berkeley, told Discovery News.

“It was only 18 years ago that most of us, myself included, thought we might never discover any planets of any sort around other stars. It was thought to be impossible. To have gone from where we were in the 1990s with nothing, to now finding Earth-sized planets in their habitable zones really boggles my mind,” Marcy said.

Before a positioning system problem sidelined the telescope in May, Kepler focused on a patch of the sky in the constellation Cygnus and dutifully assembled a digital picture every 30 minutes to send back to Earth.

Astronomers analyzed the images to find slight changes in the amount of light coming from about 150,000 target stars.

Some variations were due to star flares and other stellar phenomena, but others provided telltale clues that an orbiting planet had passed across the face of its parent star, relative to Kepler’s point of view, blocking a smidgen of light in the process.

The timing of repeat light dips indicated the planet’s distance from its host star, information scientists could then use to estimate the planet’s surface temperature. Of particular interest are planets suitably positioned for liquid surface water, as water is believed to be necessary for life.

Finally, by measuring how much starlight was blocked during a transit, scientists could calculate a candidate planet’s diameter. Smaller planets like Earth block less light than giant Jupiter-sized worlds.

A new study based on 34 months of Kepler images found 10 Earth-size planets circling in the so-called "habitable zones" of sun-like stars.

Accounting for all the other viewing angles not observed by Kepler and extrapolating from the data, the study finds that 22 percent of sun-like stars in the Milky Way have planets one- to two times the size of Earth orbiting in their habitable zones.

With about 50 billion sun-like stars in the galaxy, that means about one out of every five stars, or roughly 10 billion, have an Earth-sized planet in its habitable zone.

“This is the first time that a team has offered such a number for stars like the sun based on a thorough detection analysis,” said Kepler mission science Natalie Batalha, with NASA’s Ames Research Center in Moffett Field, Calif., told reporters on a conference call.

Read more at Discovery News

Global Warming Led to Dwarfism in Mammals -- Twice

Mammal body size decreased significantly during at least two ancient global warming events. A new finding that suggests a similar outcome is possible in response to human-caused climate change, according to a University of Michigan paleontologist and his colleagues.

Researchers have known for years that mammals such as primates and the groups that include horses and deer became much smaller during a period of warming, called the Paleocene-Eocene Thermal Maximum (PETM), about 55 million years ago.

Now U-M paleontologist Philip Gingerich and his colleagues have found evidence that mammalian "dwarfing" also occurred during a separate, smaller global warming event that occurred about 2 million years after the PETM, around 53 million years ago.

"The fact that it happened twice significantly increases our confidence that we're seeing cause and effect, that one interesting response to global warming in the past was a substantial decrease in body size in mammalian species," said Gingerich, a professor of earth and environmental sciences.

The research team also includes scientists from the University of New Hampshire, Colorado College and the California Institute of Technology. The researchers are scheduled to present their findings Friday, Nov. 1, in Los Angeles at the annual meeting of the Society of Vertebrate Paleontology.

They concluded that decreased body size "seems to be a common evolutionary response" by mammals to extreme global warming events, known as hyperthermals, "and thus may be a predictable natural response for some lineages to future global warming."

The PETM lasted about 160,000 years, and global temperatures rose an estimated 9 to 14 degrees Fahrenheit at its peak. The smaller, later event analyzed in the latest study, known as ETM2 (Eocene Thermal Maximum 2), lasted 80,000 to 100,000 years and resulted in a peak temperature increase of about 5 degrees Fahrenheit.

Teeth and jaw fossils of early hoofed mammals and primates that spanned this later climatic event were collected in Wyoming's Bighorn Basin, and the size of molar teeth was used as a proxy for body size. The researchers found that body size decreased during ETM2, but not as much as the dwarfism seen in PETM fossils.

For example, the study revealed that a lineage of early horses the size of a small dog, called Hyracotherium, experienced a body-size decrease of about 19 percent during ETM2. The same horse lineage showed a body-size decrease of about 30 percent during the PETM. After both events, the animals rebounded to their pre-warming size.

"Interestingly, the extent of mammalian dwarfism may be related to the magnitude of the hyperthermal event," said team member Abigail D'Ambrosia of the University of New Hampshire.

An ancient ungulate called Diacodexis decreased about 20 percent in size during ETM2, and the primate Cantius decreased 8 percent.

The burning of fossil fuels and the resulting release of heat-trapping greenhouse gases -- mainly carbon dioxide -- is blamed for present-day climate warming. The ancient warming events may have been caused by the release of seabed methane clathrates, a kind of methane ice found in ocean sediments, though this topic remains an area of active research, Gingerich said. Methane is a more potent greenhouse gas than carbon dioxide, and atmospheric methane is eventually transformed into carbon dioxide and water.

The parallels between ancient hyperthermals and modern-day warming make studies of the fossil record particularly valuable, said team member Will Clyde of the University of New Hampshire.

"Developing a better understanding of the relationship between mammalian body size change and greenhouse gas-induced global warming during the geological past may help us predict ecological changes that may occur in response to current changes in Earth's climate," Clyde said.

Read more at Science Daily

Important Mechanism Behind Nanoparticle Reactivity Discovered

An international team of researchers has used pioneering electron microscopy techniques to discover an important mechanism behind the reaction of metallic nanoparticles with the environment.

Crucially, the research led by the University of York and reported in Nature Materials, shows that oxidation of metals -- the process that describes, for example, how iron reacts with oxygen, in the presence of water, to form rust -- proceeds much more rapidly in nanoparticles than at the macroscopic scale. This is due to the large amount of strain introduced in the nanoparticles due to their size which is over a thousand times smaller than the width of a human hair.

Improving the understanding of metallic nanoparticles -- particularly those of iron and silver -- is of key importance to scientists because of their many potential applications. For example, iron and iron oxide nanoparticles are considered important in fields ranging from clean fuel technologies, high density data storage and catalysis, to water treatment, soil remediation, targeted drug delivery and cancer therapy.

The research team, which also included scientists from the University of Leicester, the National Institute for Materials Science, Japan and the University of Illinois at Urbana-Champaign, USA, used the unprecedented resolution attainable with aberration-corrected scanning transmission electron microscopy to study the oxidisation of cuboid iron nanoparticles and performed strain analysis at the atomic level.

Lead investigator Dr Roland Kröger, from the University of York's Department of Physics, said: "Using an approach developed at York and Leicester for producing and analysing very well-defined nanoparticles, we were able to study the reaction of metallic nanoparticles with the environment at the atomic level and to obtain information on strain associated with the oxide shell on an iron core.

"We found that the oxide film grows much faster on a nanoparticle than on a bulk single crystal of iron -- in fact many orders of magnitude quicker. Analysis showed there was an astonishing amount of strain and bending in nanoparticles which would lead to defects in bulk material."

The scientists used a method known as Z-contrast imaging to examine the oxide layer that forms around a nanoparticle after exposure to the atmosphere, and found that within two years the particles were completely oxidised.

Corresponding author Dr Andrew Pratt, from York's Department of Physics and Japan's National Institute for Materials Science, said: "Oxidation can drastically alter a nanomaterial's properties -- for better or worse -- and so understanding this process at the nanoscale is of critical importance. This work will therefore help those seeking to use metallic nanoparticles in environmental and technological applications as it provides a deeper insight into the changes that may occur over their desired functional lifetime."

The experimental work was carried out at the York JEOL Nanocentre and the Department of Physics at the University of York, the Department of Physics and Astronomy at the University of Leicester and the Frederick-Seitz Institute for Materials Research at the University of Illinois at Urbana-Champaign.

The scientists obtained images over a period of two years. After this time, the iron nanoparticles, which were originally cube-shaped, had become almost spherical and were completely oxidised.

Read more at Science Daily