Above is an artist rendition of the non-avian dinosaur Anchiornis (left) and a tinamou, a primitive modern bird (right), with snouts rendered transparent to show the premaxillary and palatine bones.
John Conway
Meet the Top 10 Meat-Eating Dinos: Photos
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Paleontologists have just assembled the most comprehensive family tree of meat-eating dinosaurs. Published in the journal Current Biology, the family tree reveals how diverse carnivorous dinosaurs were and how birds eventually evolved from them. Tyrannosaurs, including Tyrannosaurus rex , are one key group on the meat-loving dino family tree. Lead author Steve Brusatte of the University of Edinburgh's School of GeoSciences told Discovery News, "The most iconic dinosaurs of all, tyrannosaurs were more than just the 13-meter-long (nearly 43 feet long), 5-ton monster predator T. rex ." "Tyrannosaurs were an ancient group that originated more than 100 million years before T. rex , and for almost all of their evolutionary history they were small carnivores not much bigger than a human in size." New T-Rex Tracks Add to Pack-Hunting Theory
Neil Thompson, Flickr
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"Some of the rarest theropods (two-legged carnivorous dinos) of all, compsognathids are represented by about half a dozen species," Brusatte said. "They were small, sleek meat-eaters which ate small prey like lizards." One of the more recent finds, Juravenator from Germany, is known from a nearly complete fossil. Dinosaurs That Loved the Nightlife
Nobu Tamura, Wikimedia Commons
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Ornithomimosaurs were theropods called "ostrich mimic" dinosaurs -- for a reason. "Like living ostriches, they could run fast on their long legs and used their sharp, toothless beaks to eat a varied diet of small prey, plants, and perhaps even small shrimps in the water just like living flamingos," Brusatte explained. "A recent find in Canada showed that not only were ornithomimosaurs feathered, but they also had complex feathers on their arms that would have formed something of a wing, although they couldn't fly."
Nobu Tamura, Wikimedia Commons
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Brusatte describes therizinosaurs as "perhaps the weirdest theropods of all." "These were big, bulky, cumbersome dinosaurs that ate plants. They had fat barrel-shaped chests, stocky legs, and big claws on their arms," Brusatte said. For many years paleontologists argued about which group this dinosaur belonged to, only recently settling on theropods. This means they were fairly closely related to birds, despite their weird anatomy. Nests of Big-Clawed Dinosaurs Found in Mongolia
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Alvarezsaurs were among the smallest dinosaurs of all, measuring just a few feet long and weighing less than 5 kilograms (10 pounds). "Some of them had only a single functional finger on their hand, which they probably used to prod deep into the nests of bugs, which were one of their main food sources," Brusatte said. New Dinosaur Bolsters Bird-Dino Connection
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Oviraptorosaurs, were a group of small omnivores that were lightweight, lacked teeth and had tall, hollow crests on their skulls. The recently discovered Anzu -- the so-called " chicken from hell " -- came by its nickname honestly. It towered more than five feet tall, weighed more than 400 pounds, and was covered in a coat of feathers.
Mark Klingler, Carnegie Museum of Natural History
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"Troodontids were probably the smartest dinosaurs of all, as they had the largest brains relative to their body size of any dinosaur group," Brusatte said. "Most troodontids were small, fast-running dinosaurs that probably ate both meat and plants." Among the most recently discovered of this group are the small, feathered Anchiornis and Xiaotingia, which lived in China about 160 million years ago. "They look eerily similar to birds, so much so that some researchers think they could be primitive birds rather than troodontids with wings and feathers," Brusatte said. World's Earliest Bird Discovered
Nobu Tamura, Wikimedia Commons
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Dromaeosaurids were "raptor dinosaurs" that include Velociraptor from "Jurassic Park" fame. These dinosaurs were pack hunters who wielded a sharp, hyper-extendable "killer claw" on their second toe. "One of the most recently discovered dromaeosaurids is Balaur, a poodle-sized terror from Romania which had not one, but two 'killer claws' on each foot." Velociraptor Inspires Fast Running Robot
Nobu Tamura, Wikimedia Commons
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"The oldest birds, like Archaeopteryx that lived 150 million years ago in Germany, are very hard to distinguish from their closest dinosaurian relatives," Brusatte said. "Unlike living birds, they had teeth, sharp claws on their wings, and long tails." "Over the past two decades," he continued, "over 50 new species of Mesozoic birds have been discovered in northeastern China, in the same rock units as the famous 'feathered dinosaurs.' So many birds are preserved here because entire ecosystems were buried by volcanic eruptions, turning animals to stone like a dinosaur version of Pompeii." Tiny Feathered Dinosaur Found
Wikimedia Commons
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"The 10,000 species of birds that live today -- from hummingbirds to ostriches -- are modern dinosaurs," Brusatte said. "They are dinosaurs in the same way that humans are mammals. The classic body plan of living birds -- feathers, wings, wishbones, air sacs extending into hollow bones -- did not evolve suddenly but was gradually assembled over tens of millions of years of evolution. But, when this body plan finally came together completely, it unlocked great evolutionary potential that allowed birds to evolve at a super-charged rate." "They underwent a burst of evolution early in their history, which eventually led to the 10,000 species alive today -- more than twice the number of mammals." Photos: Audubon Report Names Birds at Climate Risk
Kevin Law, Wikimedia Commons
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Chicks with dino-snouts? With a little molecular tinkering, for the first time scientists have created chicken embryos with broad, Velociraptor -like muzzles in the place of their beaks.
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Kasey-Dee gets a behind-the-scenes look at how information is extracted from ancient fossils.
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The bizarrely developing chickens shed new light on how the bird beak evolved, scientists added.
The Age of Dinosaurscame to an end with a bang about 65 million years ago, due to an impact from a giant rock from space, which was probably about 6 miles (10 kilometers) across. However, not all of the dinosaurs went extinct because of this catastrophe — birds, or avian dinosaurs, are now found on every continent on Earth. [ Avian Ancestors: Images of Dinosaurs That Learned to Fly]
“There are between 10,000 and 20,000 species of birds alive today, at least twice as many as the total number of mammal species, and so in many ways it is still the Age of Dinosaurs,” study lead author Bhart-Anjan Bhullar, a paleontologist and developmental biologist at Yale University, told Live Science.
Fossil discoveries have recently yielded great insights into how birds evolvedfrom their reptilian ancestors, such as how feathers and flight emerged. Another key structure that sets birds apart from their dinosaurs ancestors is their beaks. Researchers suspect that beaks evolved to act like tweezers to give birds a kind of precision grip. The beaks help make up for the dinosaurs’ grasping arms, which evolved into wings, giving them the ability to peck at food such as seeds and bugs.
“The beak is a crucial part of the avian feeding apparatus, and is the component of the avian skeleton that has perhaps diversified most extensively and most radically — consider flamingos, parrots, hawks, pelicans and hummingbirds, among others,” Bhullar said in a statement. “Yet little work has been done on what exactly a beak is, anatomically, and how it got that way either evolutionarily or developmentally.”
To learn more about how the beak evolved, a research team led by Bhullar and developmental biologist Arkhat Abzhanov at Harvard University have now successfully reverted the beaks of chicken embryos into snouts more similar to ones seen in Velociraptorand Archaeopteryx than in birds. [ See Images of the Chicken Embryos with Dinosaur-Like Snouts]
These embryos did not live to hatch, researchers stressed. “They could have,” Bhullar said. “They actually probably wouldn’t have done that badly if they did hatch. Mostly, though, we were interested in the evolution of the beak, and not in hatching a ‘dino-chicken’just for the sake of it.”