Last week, a study found that an early dinosaur had a red mohawk and striped tail, one of the first pieces of solid evidence regarding dinosaur coloration. But a new study forthcoming in Science goes one step further, mapping in full 3D the strange plumage of the earliest-known feathered dinosaur, Anchiornis huxleyi.
Richard O. Prum, leader of the new study, was among the first to document that pigment-giving structures called melanosomes could survive fossilized for millions of years. The shape and arrangement of melanosomes help produce the color of feathers, so the scientists were able to get clues about the color of fossil feathers from their melanosomes alone [The New York Times]. British and Chinese scientists used this technique to release last week’s color study of the 125-million-year-old Sinosauropteryx, and Prum’s team applied it to the 150-million-year-old Anchiornis.
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As much as paleontologists have sorted out about the dinosaurs, one of the main aspects of their appearance—what color they were—has remained mysterious. But in a new Nature study, a team of British and Chinese scientists report that they found a way to unlock the color patters of one of the earliest feathery dinosaurs—it had a red mohawk, they say, with a red and white striped tail.
The dino in question is called Sinosauropteryx, which lived about 125 million years ago. Looking at fossils found in China, the team led by Mike Benton found what they think are the remains of feathers. And they found something inside the feathers that matches modern birds: melanosomes. These structures provide the melanin pigment in bird feathers (and human hair), and what color they are depends on the shape. “A ginger-haired person would have more spherical melanosomes, and a black-haired or grey-haired person would have more of the sausage-shaped structures,” said Professor Benton [BBC News].
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Until or unless we can create a Jurassic Park and build dinosaurs from DNA, the best way to study them may be to build dino models using materials like balsa wood, carbon fiber, and rubber bands.
That’s what a team did for a new study in the Proceedings of the National Academies of Sciences. To figure out how the 120-million-year-old winged dinosaur Microraptor gui took to the skies, the researchers used a well-preserved fossil to build their own. “We went back and forth. We thought, maybe we’ll do 3-D graphics and it’ll look really cool. But it’s more accurate to do the modeling directly from the specimen,” said Dave Burnham, a paleontologist at the University of Kansas [Wired.com].
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Earlier this month DISCOVER covered the 213-million-year-old fossils of the theropod Tawa hallae, a dinosaur ancestor that could show how early dinos spread around the world. Now, in a study (in press) in the Proceedings of the National Academy of Sciences, another research team has uncovered a surprise in the bones of a theropod from almost 100 million years later. By that time, these creatures may have adopted a clever new weapon: venom.
Sinornithosaurus lived 125 million years ago in what’s now China, and while it might have been covered in feathers (and the size of a turkey), the researchers say it attacked like modern rear-fanged snakes. Rear-fanged snakes don’t inject venom. Instead, the toxin flows down a telltale groove in a fang’s surface and into the bite wound, inducing a state of shock [National Geographic].
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Sixty-five million years ago—we know when the dinosaur story ends. But the beginning of the dinosaur age is hazier, due to the small number of distinct fossils with which to set a time frame. But now scientists have turned up fossils in New Mexico of an early dinosaur ancestor, they report tomorrow in the journal Science, one that points to South America as the possible place of dinosaur origin.
The feathered beast, named Tawa hallae, was the size of a large dog and sported a long neck and tail, a slender snout, and sharp, curved teeth to catch and kill its prey [The Guardian]. Tawa hallae is an early theropod, meaning it is related to birds and the mighty T. Rex.
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You’d think something with as much awesome power as the talons on birds of prey would be among the better-understood appendages in the animal kingdom. Not so, say the authors of a new in PLoS One, but they’ve rectified the situation by analyzing 24 different birds to reveal the evolution and use of talons by the owl, osprey, falcon, and more.
They describe how accipitrids, which include hawks and eagles, have two giant talons on their first and second toes [as in pictures A and B]. These give them a secure grip on struggling game that they like to eat alive, “so long as it does not protest too vigorously. In this prolonged and bloody scenario, prey eventually succumb to massive blood loss or organ failure, incurred during dismemberment” [Wired.com].
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A thrilling set of ancient crocodile fossils have been unearthed in northern Africa. A “saber-toothed cat in armor” and a pancake-shaped predator are among the strange crocodile cousins whose bones have been found beneath the windswept dunes of the Sahara, archaeologists say [National Geographic News].
At a news conference organized by the National Geographic Society, which sponsored the research, scientists announced that the fossils represent 5 species; 3 new species and 2 that were previously known. These ancient croc ancestors, known as crocodilyforms, are unlike any crocodiles encountered in the Northern Hemisphere, according to the research team. Their findings are detailed in the journal ZooKeys.
The crocs were spectacularly diverse, and included a species that ate dinosaurs, two that grew up to 20 feet long, and two that had long legs for quick movement on land but also had long tails for swimming. The three new species are:
• BoarCroc (Kaprosuchus saharicus), a 20-foot meat-eater. It used its snout for ramming and three sets of dagger-shaped fangs for slicing dinosaurs it ate.
• PancakeCroc (Laganosuchus thaumastos): a 20-foot-long, squat fish-eater with a 3-foot long flat head with spike-shaped teeth.
• RatCroc (Araripesuchus rattoides), a 3-foot-long plant and grub eater with buckteeth used for digging [Chicago Sun-Times].
The two previously known species are nicknamed DuckCroc, a three-foot long, long-legged croc that feasted on fish and frogs, and DogCroc, another small and lanky croc that mostly ate plants and grubs.
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The world domination achieved by such fearsome bipedal dinosaurs as the T. rex may have been a result of their warm-blooded biology, according to new research. For decades, scientists assumed that because dinosaurs resembled lizards, they were cold-blooded as well, their internal temperature rising and falling with the outside world. However, birds are warm-blooded, and the fact that birds seem to be descended from dinosaurs raises the question of whether their ancestors were as well [LiveScience]. The new study, published in the journal PLoS ONE, examined the anatomy of 14 species of bipedal dinosaurs, and argues that many of them needed more energy to power their massive leg muscles than a cold-blooded metabolism could provide.
Lead researcher Herman Pontzer based his findings on the estimated amount of energy dinosaurs must have expended moving about. Recent research by Dr Pontzer has shown that the energy cost of walking and running is strongly associated with leg length. Hip height – the distance from the hip joint to the ground – can predict the observed cost of locomotion with 98 per cent accuracy for a wide range of land animals [Telegraph]. The research team also used measurements of fossilized leg bones to determine the leg muscle mass of each species, and found that the muscles would have required a great deal of energy during walking and running.
The dinosaurs would have benefited from a warm-blooded metabolism, Pontzer says, because they could have been agile and active even when the temperature dipped, and could have therefore spread through areas with colder climates. But there would also have been a downside: Maintaining a stable internal temperature … costs a lot of energy and requires the animals to feed more regularly [The Guardian]. At any rate, the new results aren’t likely to convince paleontologists who aren’t in the warm-blooded camp, and you can expect the debate to continue.
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Image: PLoS ONE / Herman Pontzer, et al.
Could the Chicago Field Museum’s mighty Tyrannosaurus Rex, a dino named Sue, have been toppled by a lowly parasite? According to a recent study in the journal PLoS ONE, a microbe commonly found in pigeons may be responsible for holes in the dinosaur’s mandible, holes that were previously thought to be bite marks. Paleontologists compared a similar infection in a modern predatory bird to the T-Rex holes and found surprising similarities.
The researchers think the parasite, a protozoan named Trichomonas gallinae, settled in the back of Sue’s throat, and in nine other Tyrannosaurs … studied with similar holes. The parasite caused inflammation that eventually damaged the jawbone [Los Angeles Times], first forming lesions and then eroding the bone away. The inflammation would have choked off the dino’s esophagus, they say, eventually starving the T. Rex to death.
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A feathered dinosaur unearthed in a Chinese quarry has added another solid piece of evidence to the theory that birds descended from dinosaurs. The newly uncovered fossil of the species Anchiornis huxleyi dates from the Late Jurassic period, 151-161 million years ago, and therefore predates the earliest known bird, the Archaeopteryx. Paleontologists say this represents the final proof that dinosaurs were ancestral to birds. “Drawing the tree of life, it’s fairly obvious that feathers arose before Archaeopteryx appears in the fossil record” [BBC News], says paleontologist Michael Benton.
The creature, described in a paper [pdf] in Nature, was covered in the short feathers known as “dino-fuzz,” and had longer feathers on both its forelimbs and its back legs that formed primitive wings. The four-winged dinosaurs also had feathers on their feet and wing-like attachments on the arms and legs. But they could probably only glide, as their plumage was insufficient for powered flight [Nature News].
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80beats: New Fossil Suggests That Fuzzy Dinosaurs Were Plentiful
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80beats: “Bizarre” and Fluffy Dino May Have Used Feathers to Attract Mates
Image: Zhao Chuang, Xing Lida. An artist’s rendering of Anchiornis huxleyi.
Call it an evolutionary beta test. About 125 million years ago a dinosaur stalked the world, and this predator had a familiar shape: It stood on strong back legs but had runty forelimbs, had a whip-like tail, and had a disproportionately large head with vicious teeth. But while that sounds like a description of the mighty Tyrannosaurus rex, this beast actually lived 35 million years before T. rex–and it was only 9 feet tall.
The discovery of the new species, which has been named Raptorex kriegsteini, has upended previous theories about how the king of the lizards evolved. Says study coauthor Stephen Brusatte: “The thought was these signature Tyrannosaurus features evolved as a consequence of large body size…. They needed to modify their entire skeleton so they could function as a predator at such colossal size” [The New York Times]. Instead, it appears that these features evolved in the early ancestors of T. rex, and that over the epochs the animals simply scaled up.
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A prehistoric armadillo-like animal swung its tail like a baseball bat, taking advantage of the “sweet spot” the same way tennis and baseball players do today, according to a study published in the journal Proceedings of the Royal Society B.
The tail sported spikes at a specific location that allowed the mammals, known as glyptodonts, to deliver a strong blow while minimizing the risk of harming the tail, the researchers found; spiny-tailed dinosaurs may have used the same mechanism. Known as the “sweet spot” today in sports like baseball, this so-called “center of percussion” helps athletes avoid wrist injuries. “The center of percussion is a point where you can deliver a very powerful blow with a baseball bat, a tennis racket, a sword, an axe or any hand-held implement, but the forces against your hands are almost zero” [Discovery News], said lead author Rudemar Ernesto Blanco. The glyptodont, which went extinct about 8,000 years ago after its emergence about 2.5 million years ago, would have swung its tail about 15 meters per second–about as fast as a modern-day tennis player swinging his or her racket.
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The oldest known tree-dwelling vertebrate lived 30 million years before the dinosaurs, scientists have found. The animal, known as Suminia getmanovi, had opposable thumbs and long hands, which would have allowed it to live in trees, according to a study published in the journal Proceedings of the Royal Society B.
A team of researchers found that Suminia, which lived about 260 million years ago, had disproportionately long arms and slender, curved fingers that were well-adapted to grabbing tree branches. But perhaps most importantly, one finger on each hand and foot was “opposed” to the rest, much like a thumb. “It’s the first time in the fossil record that we’ve seen evidence of an opposable thumb,” [said lead researcher Jorg Frobisch], adding that the creature was an early ancestor of mammals [BBC News]. The 12 well-preserved Suminia skeletons the scientists analyzed, which were found in Russia the 1990s, predate by 100 million years what was previously thought to be the earliest tree-dwelling animal.
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Some dinosaurs coped with the cold of winter by venturing beneath the Earth’s surface, according to a study to be published in the journal Cretaceous Research. Three fossilized burrows found in southeastern Australia are the second group of such tunnels found on Earth and, dating back 110 million years, are the oldest.
When dinosaurs roamed the Earth, these burrows were within the Antarctic Circle and temperatures dipped below freezing during the winter. Also, periods of little sunlight likely led to cyclical shortages in vegetation. The burrows support the hypothesis that instead of migrating to escape the cold winters of the Cretaceous period, dinosaurs ventured underground, like modern animals such as alligators and coyotes. The only other known dinosaur burrow was discovered in 2005 in Montana, US. Described two years later, this burrow dated from 95 million years ago and contained the bones of an adult and two juveniles of a small new species of dinosaur called Oryctodromeus cubicularis [BBC News]. Burrows that snaked below the ground may have provided a haven offering protection from predators, along with stable temperatures, constant humidity levels and a place to tend to offspring.
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Dinosaurs are objects of eternal fascination to we puny humans because of their sheer size. Some, like the long-necked sauropods, are thought to have had eight times the mass of an African elephant, the largest modern land animal.
Now a new model from zoologist Brian McNab suggests that the secret of dinosaurs‘ size was really quite simple: They had plenty to eat, and didn’t have to expend much energy in their daily lives. Says McNab: “Like couch potatoes sitting within easy reach of high calorie foods, the gargantuan size of dinosaurs most likely stems from the abundance of resources available, coupled with low energy expenditures” [Telegraph]. McNab’s findings also contribute to the long-running debate between paleontologists about whether dinosaurs were warm-blooded or cold-blooded creatures.
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