Asian fossil discovery may help explain how tyrannosaurs became dominant predators

June 17, 2016 Leave a comment
Timurlengia euotica - March 2016 - courtesy

This artist’s conception shows the tyrannosaur Timurlengia euotica in its environment 90 million years ago, accompanied by two flying reptiles (Azhdarcho longicollis). The fossilized remains of a the horse-sized dinosaur help explain how Tyrannosaurus rex and its close relatives became top predators. The paper describing the discovery was published in March in the Proceedings of the National Academy of Sciences. Illustration by Todd Marshall.

Researchers have discovered 90 million-year old fossils of an early tyrannosaur that may help improve scientists’ understanding of how that group of dinosaurs evolved into the predatory giants that later roamed North America.

The horse-sized animal, which would have likely weighed about 250 kilograms, apparently had impressive hearing ability. Its capacity to hear low frequency sounds can be deduced from an elongated cochlear duct.

Named Timurlengia euotica, the newly-identified tyrannosaur helps fill a gap in knowledge about how the relatively small theropods, which had to compete with larger allosaurs, evolved into some of the largest land predators ever known.

The discovery indicates that the tyrannosaur clade probably gained the sensory tools needed to become apex predators before late Cretaceous enormity took hold.

“Tyrannosaurs had to get smart before they got big,” Dr. Stephen L. Brusatte, a paleontologist at the University of Edinburgh in the United Kingdom and lead author of the paper describing the discovery, said.

Enormity on the scale so obviously presented by later tyrannosaurs like Tyrannosaurus rex, which stood about five meters tall and about 12 meters long and weighed about 3,600 kilograms, evolved during the last 20 million years of the dinosaurs’ dominance of Earth.

Researchers found a brain case, which they then subjected to a computed microtomography (CT) scan. That scan revealed not only the animal’s inner ear structure, but also likely similarities between T. euotica‘s brain and the brain of Tyrannosaurus rex.

Brusatte wrote in The Conversation that these features likely helped T. euotica become a very skilled tracker of prey.

“Their intelligence and sharp senses made tyrannosaurs perfectly equipped to swoop into the top-predator role,” he wrote.

As the tyrannosaur head became larger, it became more useful for hunting.

“Their heads became giant killing machines and their arms, now unnecessary, shrunk down to nubbins,” Brusatte wrote in The Conversation feature.

The fossilized braincase, along with a variety of other bones, had been stored in a museum for about ten years. Brusatte and his colleagues examined them in 2014.

Reconstructed T. euotica skeleton

This is a reconstructed skeleton of Timurlengia euotica with discovered fossilized bones, highlighted in red, and other bones remaining to be discovered inferred from other related species of tyrannosaurs in white. Individual scale bars for the pictured fossilized bones each equal 2 centimeters. The fossilized remains of T. euotica may reveal how Tyrannosaurus rex and its close relatives became top predators. Graphic (c) National Academy of Sciences.

“Working on Timurlengia has been one of the highlights of my career,” Brusatte said. “It gives us a glimpse of what the ancestor of T. rex was – a tyrannosaur right on the cusp of becoming huge.”

The fossils were found in the remote Kyzylkum Desert of Uzbekistan. Their significance was described in a paper published in March in Proceedings of the National Academy of Sciences.

Astronomers discover moon orbiting dwarf planet Makemake

June 17, 2016 Leave a comment
makemake's moon

This image obtained by the Hubble Space Telescope in April 2015 shows a moon – the first discovered – in orbit around the dwarf planet Makemake. The tiny satellite, located just above Makemake in this image, is barely visible because it is almost lost in the glare of the very bright dwarf planet. Image courtesy NASA, European Space Agency, Southwest Research Institute.

Makemake, a dwarf planet far beyond Pluto in the Kuiper Belt, has a moon.

Imagery obtained by the Hubble Space Telescope detected the satellite last April, according to a recently published paper.

The moon, which has been temporarily catalogued as S/2015 (136472) 1 and nicknamed MK2, is about 100 miles in diameter. It was observed orbiting Makemake from a distance of about 13,000 miles.

MK2 probably orbits Makemake in an orientation that makes it difficult for astronomers to observe the moon.

“Our preliminary estimates show that the moon’s orbit seems to be edge-on, and that means that often when you look at the system you are going to miss the moon because it gets lost in the bright glare of Makemake,” Dr. Alex H. Parker, a planetary scientist at Southwest Research Institute in Boulder, Colo., said.

Parker led the team that analyzed the Hubble image of MK2.

One implication of the Makemakean moon’s discovery is an increased ability to measure Makemake’s mass and density.

To measure the dwarf planet’s mass, scientists will need to overcome the challenges inherent in observing MK2’s orbit. If they succeed in doing so, and because the distance from Earth to Makemake is already known, it would be possible to use the orbital period and the mean distance of MK2 from Makemake to determine Makemake’s mass.

To determine Makemake’s density, scientists must know its volume, which in turn requires knowledge of the dwarf planet’s diameter. Makemake’s diameter is about 1,500 kilometers.

Once the volume is determined, density can be calculated by dividing Makemake’s mass by its volume.

makemake-artist-view

Early artist’s impression of Makemake. Courtesy NASA.

Astronomers used a camera on the Hubble Space Telescope to find MK2. That instrument, called Widefield Camera 3, is able to capture images across the radiation spectrum.

Widefield Camera 3 has a 16 megapixel capacity and can capture an image as large as 160 arcseconds by 160 arcseconds in size.

Makemake is the second-brightest object, after Pluto, in the Kuiper Belt and is, like Pluto, covered with methane ice.

The dwarf planet, which was discovered in 2005, is named for a deity that is worshiped by native people of Easter Island.

In addition to Makemake, there are four other dwarf planets in the solar system: Pluto, Eris, Haumea, and Ceres.

With the discovery of MK2, astronomers now know that all of the solar system’s dwarf planets have moons.

Southwest U.S. readies for possible record-breaking heat

June 15, 2016 Leave a comment

The southwestern United States may be facing near record-breaking summer heat during the next few days.

According to the National Weather Service, major cities in Arizona, Nevada, and even southern California will experience temperatures of at least 100 degrees Fahrenheit at the beginning of next week.

The forecast officially calls for Phoenix to hit 117 degrees on Sunday and 118 degrees on Monday. Las Vegas may hit 110 degrees on Monday and Tuesday, while Tucson’s temperature could reach 114 degrees on Sunday and 112 degrees on Monday.

Meteorologist Bob Henson, writing at the Weather Underground blog, thinks it could be warmer.

WU forecast SW June 2016

Graphic courtesy Weather Underground.

So does Ryan Maue, a meteorologist affiliated with Weatherbell Analytics. Maue predicts that the temperature in Phoenix will reach 120 degrees on Monday.

The all-time hottest temperature in Phoenix is 122 degrees, which was reached in 1990. At least one forecast map shows that the metropolis in central Arizona’s Salt River Valley might reach 120 degrees on Monday.

The Valley of the Sun has experienced four straight record-breaking warm days this month (June 3-7), as well as its earliest 115 degree day in recorded history. If Phoenix reaches 116 degrees on Sunday, it would be the hottest day ever recorded in the city prior to the summer solstice.

The heat record in Las Vegas (most recently on June 30, 2013) and Tucson (June 26, 1990) is 117 degrees, while Yuma’s all-time mark is 124 degrees (July 28, 1995).

Los Angeles could reach 101 degrees on Monday, June 20. That is not close to the city’s all-time record high temperature of 113 degrees.

Southwest temperatures

This graphic shows the forecasted high temperatures on June 20, 2016. Graphic courtesy Weatherbell Analytics, National Weather Service.

Records maintained by the National Centers for Environmental Information, an agency of the National Oceanic & Atmospheric Administration, show that record high temperatures are much more common in the U.S. this year than are record low temperatures.

South Pole reaches 400 ppm of carbon dioxide

June 15, 2016 Leave a comment
South Pole carbon dioxide record - courtesy NOAA

This graphic shows the rise in daily average carbon dioxide levels at the South Pole to 400 parts per million on May 23. It’s the first time this has happened in at least four million years. Data for 2014-present recorded NOAA’s greenhouse gas monitoring network. Graphic courtesy NOAA.

The concentration of carbon dioxide in the atmosphere above our planet’s South Pole reached the worrisome threshold of 400 parts per million.

At least four million years have past since the last time carbon dioxide was so plentiful in the air above the South Pole, according to a statement announcing the milestone released Wednesday by the National Oceanic & Atmospheric Administration.

No region of Earth remains below the 400 ppm threshold.

“The far southern hemisphere was the last place on earth where CO2 had not yet reached this mark,” Pieter Tans, the lead scientist of NOAA’s Global Greenhouse Gas Reference Network, said. “Global CO2 levels will not return to values below 400 ppm in our lifetimes, and almost certainly for much longer.”

The South Pole is slower to demonstrate increases in atmospheric greenhouse gas concentrations driven by human combustion of fossil fuels because that region is so remote from the populated, and economically developed, areas of Earth.

Another federal government entity, the National Center for Atmospheric Research in Boulder, Colo., recently warned that the South Pole would soon cross the 400 ppm threshold.

Atmospheric co2 ppm - graphic courtesy Scripps Institution of Oceanography, graphic by Eric Morgan

This graphic illustrates the atmospheric concentration of carbon dioxide near Antarctica in January, just as air masses over the Southern Ocean began to exceed 400 parts per million of CO2. Graphic courtesy Scripps Institution of Oceanography, illustration by Eric Morgan.

“Throughout humanity, we have lived in an era with CO2 levels below 400 ppm,” Ralph Keeling, director of the CO2 Program at the Scripps Institution of Oceanography, said in an NCAR statement released May 12 . “With these data, we see that era drawing to a close, as the curtain of higher CO2 spreads into the Southern hemisphere from the north. There is no sharp climate threshold at 400 ppm, but this milestone is symbolically and psychologically important.”

NOAA data obtained at the South Pole indicates that the atmospheric concentration of carbon dioxide there was about 336 ppm in 1980 and has generally been rising since that time.

 

Largest known planet to orbit two suns is discovered

June 15, 2016 Leave a comment
Kepler planet comparison - courtesy NASA GSFC, graphic by Lynette Cook

This graphic shows the relative size of several known circumbinary planets. Kepler-1647b is about the size of Jupiter. Courtesy NASA Goddard Space Flight Center, graphic by Lynette Cook.

Scientists have found a planet about the size of Jupiter orbiting two stars in a nearby solar system, marking the largest known example of a world with multiple suns.

The circumbinary planet, which has been named Kepler-1647b, is in the constellation Cygnus, about 3,700 light years from Earth. Astronomers used the Kepler Space Telescope to discover it.

“It’s a bit curious that this biggest planet took so long to confirm, since it is easier to find big planets than small ones,” Dr. Jerome A. Orosz, an astronomer at San Diego State University and a co-author of a paper documenting the discovery, said. “But it is because its orbital period is so long.”

Kepler-1647b’s orbital period is 1,107 days, which means it takes longer to orbit its stars than any other known exoplanet takes to orbit either one star or two.

The planet’s circumbinary orbit made it more difficult to find than would be the case with an exoplanet that circles one star.

“The transits are not regularly spaced in time and they can vary in duration and even depth,” Dr. William F. Welsh, another SDSU astronomer and co-author of the paper explaining the discovery, said.

Kepler-1647b orbit

This graphic provides a “bird’s eye” view comparison of the orbits of the Kepler circumbinary planets. Kepler-1647 b’s orbit, shown in red, is much larger than the other planets (shown in gray). For comparison, Earth’s orbit is shown in blue. Graphic courtesy NASA Goddard Institute for Space Studies, graphic by B. Quarles.

A gas giant, Kepler-1647b is has a similar age as Earth – about 4.4 billion years. The two stars it orbits are similar to our sun, with one being a little larger than the Sun and the other slightly smaller than Earth’s star.

The discovery of Kepler-1647b is described in a paper to be published in Astrophysical Journal.

 

 

 

 

May is eighth straight warmest month, NASA says

June 15, 2016 Leave a comment
May 2016 temperatures

This map indicates the extent to which temperatures on Earth deviated from the 1951-1980 average. Ocean data are not used over land nor within 100 kilometers of a reporting land station.The gray areas on the map indicate missing data. Map courtesy NASA Goddard Institute for Space Studies.

May continued a streak of record setting hot months as average temperatures were nearly a whole degree Celsius above the previously hottest May.

NASA’s Goddard Institute for Space Studies said Tuesday that the mean global temperature during the year’s fifth month was 0.93 degrees Celsius, or 1.67 degrees Fahrenheit, than the average for May.

That made May 2016 the eighth consecutive month, according to NASA records, to break the record for warmth.

The previous record-holding May occurred in 2014.

Japan’s meteorological agency reached a slightly different conclusion, concluding that May 2016 was the second-warmest May on record.

Another U.S. federal agency, the National Oceanic & Atmospheric Administration, has yet to release its measurement of average May temperatures. NOAA uses the same data as NASA but analyzes measured temperatures differently.

NASA’s method depends on a dataset called the GISS Surface Temperature Analysis. GISTEMP includes records from 6,300 meteorological stations scattered around the planet, ship-based and satellite observations of sea surface temperatures, and research stations in Antarctica. The GISTEMP data goes back to 1880.

Although May was another record-setting month, in terms of heat, it was not as anomalous as the seven prior months. Between October 2015 and April 2016 the monthly average temperature exceeded the previous record-holding month by at least one degree Celsius.

The explanation for the lessened disparity in heat between May 2016 and previous Mays in the temperature record might be related to the approaching end of a powerful El Nino event.

Nevertheless, at least according to one climate scientist, May’s record-setting mean temperature means that the rolling 12-month average has now exceeded one degree Celsius above the norm for the period 1951-1980.

 

Researchers discover possible Earth-like exoplanet orbiting ultracool dwarf star

MIT - May 2016 - Earthlike exoplanets

This illustration depicts an artist’s imagined view of the three planets orbiting an ultracool dwarf star just 40 light-years from Earth. The exoplanets were discovered using the TRAPPIST telescope at European Southern Observatory’s La Silla Observatory. In the illustration, one of the inner planets is seen in transit across the disc of its tiny and dim parent star. Image courtesy European Southern Observatory, artist’s conception by M. Kornmesser.

Astronomers have discovered three exoplanets in a nearby star system that may be comparable to the size of Earth and Venus and one of them may also be located at distance from its star to experience temperatures similar to our planet.

The planets are about 40 light years from our planet and orbit a dwarf star that is about one-eighth the size of our sun, or approximately the size of Jupiter. The dwarf star, which astronomers consider to be “ultracool,” is so much cooler than our sun that the system’s habitable zone is much closer to it than in our solar system.

A star’s habitable zone is the area of its star system in which temperatures may be hospitable to environmental conditions amenable to life.

Two of the exoplanets have orbital periods of less than three days; they probably receive two-to four times the amount of solar radiation that Earth does.

The third and most distant of the exoplanets experiences a year that is at least four and as many as 73 days long.

“These planets are so close, and their star so small, we can study their atmosphere and composition, and further down the road, which is within our generation, assess if they are actually inhabited,” Julien de Wit, a postdoctoral researcher at Massachusetts Institute of Technology and a co-author of the paper announcing the discovery, said.

The two exoplanets closest to their star are likely tidally locked to it, meaning that one side of the planet always faces the star. Those two planets are generally too hot on their day-sides, and too cold on their night sides, to support life, though the team of scientists that published the paper describing them said that there may be small areas on their western hemispheres that might be temperate enough to do so.

The third planet from the star could be in its habitable zone, meaning liquid water could occur on its surface.

The three exoplanets are the first ever discovered orbiting an ultracool dwarf star.

Researchers used the TRAPPIST instrument in Chile to find the exoplanets. Because their star emits so little radiation, compared to larger stars, it cannot be seen with an optical telescope.

TRAPPIST, which is an acronym for TRAnsiting Planets and PlanetesImals Small Telescope, detects radiation in the infrared band of the spectrum. Starting in September 2015 the scientists periodically detected a lessening of the amount of the star’s infrared radiation detected by the instrument. That indicated the likelihood that several objects were passing in front of it.

The paper describing the discovery of the exoplanets was published online in the May 12 edition of Nature.

 

Bee learning ability slowed by pesticides, study finds

April 28, 2016 Leave a comment
Bumble bee - courtesy Wikimedia

This image shows a bumble bee loaded with pollen. Image courtesy Wikimedia.

Bees exposed to pesticides might have a harder time learning how to pollinate flowers than those who are not exposed to the substances, a new study suggests.

The paper, which was published in the March 14 edition of Functional Ecology, is the first to show that neonicotinoids, a class of pesticides that is now commonly used to protect a variety of agricultural crops, may impact the ability of individual bees to forage for nectars and pollen. It examined the impact of a compound called thiamethoxam on bumblebees.

“What we found is that bees exposed to pesticide initially collected more pollen, but it took them more visits to flowers to properly ‘learn’ this behavior,” Dr. Dara Anne Stanley, the lead author of the paper and a researcher at the University of KwaZulu-Natal in South Africa, said. “Control bees collected less pollen, but learned the behavior properly after visits to less flowers. Therefore control bees may be investing more time in learning this behavior properly.”

That result is consistent with the findings of other recent studies. For example, a paper published last year showed that bumblebees exposed to pesticides suffer memory loss. Another paper published in 2015 demonstrated that bumblebee colonies that encounter neonicotinoids tend to forage for pollen less than those colonies that do not come into contact with the compounds.

Neonicotinoids appear to target the area of a bee’s brain that governs the insect’s behavior.

“Neonicotinoid pesticides in particular target a region of the insect brain called the nicotinic acetylcholinase receptors (nAChRs) where they target cholinergic signaling by inhibiting acetylcholinesterase,” Stanley said in an e-mail message. “As the nAChRs have been associated with behavior in insects, in particular learning and memory, this means these pesticides at sub-lethal doses have the potential to cause changes in insect behavior.”

The term cholinergic signaling refers to the movement of neurotransmitters in an organism’s nervous system. Those compounds carry information across synapses.

If the pesticide is used near a bee colony, then its impacts on the ability of individual bees to obtain pollen could negatively affect the whole colony.

“As bees in particular display a range of sophisticated behaviors involved in navigation, foraging etc, these pesticides have the potential to effect foraging success and ultimately colony health,” Stanley said.

That may be less of a worry for honeybees, which live in large colonies. Stanley explained that a recent study conducted in Sweden indicated that honeybees are affected by exposure to pesticide-treated crops less rapidly than bumble bees.

“Honeybee colonies are extremely large with thousands of workers, and therefore the effects of pesticides on individuals would have to be very strong to see any impacts on the whole colony, and if there are impacts it could take many years to become apparent,” she said. “However, bumblebee colonies are much smaller and therefore any impacts on individuals are likely to be much more influential on the colony as a whole. When it comes to solitary bees, each individual female builds her own nest, so they are likely to be even more susceptible to any behavioral effects on individuals.”

While sale of neonicotinoids are now worth about $2.6 billion per year to manufacturers, the substances are thought to be dangerous to many other organisms. A series of papers published in 2014 indicated that they “exhibit very high toxicity” to many invertebrates and that some bird and fish species are especially vulnerable to harm caused by the use of neonicotinoids.

305 million year-old ancestor of spiders is identified

April 28, 2016 Leave a comment
Early arachnid

Idmonarachne brasieri lived about 305 million years ago. Image courtesy University of Manchester.

Paleontologists have identified an ancestor of modern spiders that lived before the dinosaurs began their long domination of the planet.

The arachnid’s fossil remains were found during the mid-1970s in Europe embedded in an iron-rich mineral, siderite, that is difficult for x-rays to penetrate. Researchers used a synchotron, which emits more powerful x-rays, to identify the organism.

Named Idmonarachne brasieri, the organism was likely a member of a group of arachnids called uraraneids. These animals lacked spinarets, which modern spiders use to spin webs, and instead would have discharged silk in sheets.

“Our new fossil occupies a key position in the evolution of spiders,” Dr. Russell Garwood of the University of Manchester, the lead author of a paper documenting the discovery, said. “It isn’t a true spider, but has given us new information regarding the order in which the bits of the anatomy we associate with spiders appeared as the group evolved.”

Scientists know little of the origin of spiders and the evolutionary path by which such anatomical features as spinarets formed is not well understood.

The paper appears in the March 30 edition of Proceedings of the Royal Society B.

 

Fossils of largest-ever marine crocodile found in Africa

April 28, 2016 Leave a comment

Scientists have found evidence that a ocean-dwelling crocodile about 10 meters long once roamed the area we now know as north Africa.

The beast, which also likely weighed at least three tons, lived about 120-130 million years ago.

Dubbed Machimosaurus rex, the crocodile is the largest known of its kind. A marine reptile, it thrived at a time in Earth’s geologic history when the land now known as north Africa was submerged under an ocean.

machimosaurus-rex-reconstruction

Machimosaurus rex was a marine reptile, about 12 meters long, that swam in Cretaceous oceans. Illustration courtesy University of Alberta, illustration (c) Davide Bonadonna. All rights reserved.

Researchers discovered the species in 2014 when a skull measuring almost two meters in length was unearthed in Tunisia. The specimen has teeth that are are shaped like bullets, which the creature may have used to crush the carapaces of marine turtles.

The length of the animal is an estimate, based on the dimensions of similar organisms within the animal’s genus that lived during the Jurassic and Cretaceous periods.

“We have been digging in that area since 2011 because the rocks there are nothing like other places,” Federico Fanti, a paleontologist at the University of Bologna in Italy and lead author of the paper documenting the find, said in a statement. “Globally, good fossils are rare from this age—130 million years ago.”

Fanti and his team later found more of the specimen, including vertebrae, but were not able to remove those parts of the fossil because of ongoing unrest in the country.

The species is part of a larger genus that was first discovered in the nineteenth century. Among M. rex‘s close relatives are crocodilians that roamed Jurassic and Cretaceous period seas that then covered the part of Earth now known as Europe.

M. rex was the largest of the teleosaurids (marine crocodiles) in its genus.

While large, the croc is not the largest known from the planet’s long history of life. At least several species of freshwater crocodile that lived during the time of the dinosaurs, Sarcosuchus imperator and those in the genus Deinosuchus, were more imposing than M. rex.

S. imperator was about two meters longer than M. rex, while some Deinosuchus species may have been only slightly longer than M. rex.

The paper documenting the discovery of M. rex was published online in the Jan. 10, 2016 edition of Cretaceous Research.

 

 

 

 

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