This is a dromaeosaurid dinosaur species from the Upper Cretaceous of Alberta, Canada. The type (and only) specimen was discovered in the Horseshoe Canyon Formation, near Drumheller, Alberta. It had a relatively short, massive skull with slender lower jaws and long, highly curved teeth (the rest of the skeleton is unknown). Similar teeth are found in the Upper Cretaceous Lance Formation. Atrociraptor seems to be most similar to Deinonychus.

    Philip Currie, head of dinosaur research at the Royal Tyrrell Museum in Drumheller, Alta. named the creature Atrociraptor marshalli, or savage robber. It is related to the swift velociraptors of Jurassic Park fame, but is smaller with a shorter, deeper snout like a bulldog.
    Paleontologists discovered a partial skull of the Atrociraptor near Drumheller, Alta. in 1995. Currie describes the find and how its dagger-like teeth set it apart in the book Feathered Dragons: Studies on the Transition from Dinosaurs to Birds. Altrociraptor is the first new meat-eating dinosaur to be discovered in Alberta in 14 years, Currie said. People have been searching the fossil-rich area for 125 years.  Remains of smaller dinosaurs like Altrociraptor are relatively rare because they don't preserve as well, he said. Based on studies of a related specimen found in Montana, the raptors probably hunted in packs, Currie said. 
      Raptors like Altrociraptor are considered the closest non-avian relatives of a Archaeopteryx, a feathered fossil with both reptile and bird features. Although no dinosaur specimens have been found with preserved feathers in North America, many of the Late Cretaceous species from Alberta and other regions are closely related to the feathered dinosaurs of China.
     According to Currie, feathers were probably widely distributed amongst meat-eating dinosaurs, and we can no longer be sure that fossilized feathers found in Cretaceous rocks all belong to birds. It is highly likely, in fact, that most of the Late Cretaceous theropods of the Northern Hemisphere, including tyrannosaurs, were feathered. Most evidence suggests that feathers were initially used for insulation and display. Regardless of the widespread presence of feathers in dinosaurs, the theory that birds evolved from dinosaurs is supported by more than 125 osteological characters that are uniquely shared by these two groups of animals.

Currie received a 2004 Michael Smith Award for outstanding achievement in the promotion of science in Canada. The award recognized Currie's ongoing efforts to bring information on dinosaurs and their world to Canadians through children's books, public lectures and countless radio and television programs, including National Geographic Magazine, New York Times, Time Magazine, NBC's Today Show, PBS's Nova series, and a CBS primetime program on dinosaurs. In addition to his position at the Royal Tyrrell Museum, Currie teaches at the University of Calgary and the University of Saskatchewan.

REUTERS / Stephanie Abromowicz An undated handout image shows an artist's impression of how a newly discovered dinosaur, called Juraventor, might look after a perfectly preserved fossil of a 150 million-year-old dinosaur was found in southern Germany. NEW YORK -- A beautifully preserved fossil from southern Germany raises questions about how feathers evolved from dinosaurs to birds, two paleontologists argue in a study published Thursday.

The 150 million-year-old fossil is a juvenile carnivorous dinosaur about 2½ feet long that scientists named Juravenator, for the Jura mountains where it was found.

It would have looked similar in life to the fleet-footed predators that menaced a young girl on the beach during the opening scene of “The Lost World,” the second Jurassic Park movie.

The fossil's exceptionally well-preserved bone structure clearly puts it among feathered kin on the dinosaur family tree. Because all of its close relatives are feathered, paleontologists would expect Juravenator to follow suit.

But a small patch of skin on the creature's tail shows no sign of feathers. And the skin also doesn't have the follicles that are typical of feathered dinosaurs, said Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles County. He and Ursula B. Gohlich of the University of Munich describe the fossil in Thursday's issue of the journal Nature.

“It has a typical scaly dinosaurian skin,” Chiappe said.

The paleontologists believe Juravenator's closest known relative may have been a fully feathered dinosaur from China, Sinosauropterix.

There are a number of possible explanations for Juravenator's nakedness. Feathers could have been lost on the evolutionary line leading to Juravenator after arising in an ancestor to both it and its feathered relatives. Or feathers could have evolved more than once in dinosaurs, cropping up in sister species at different times and places. It is also possible that this particular fossil of Juravenator, which appears to be a juvenile, only grew feathers as an adult or lost its feathers for part of the year.

But there is another possibility as well, said Mark Norell, curator of paleontology at the American Museum of Natural History: It is entirely possible that Juravenator did have feathers, but they simply failed to fossilize.

“Feathers are really just difficult things to preserve,” Norell said.

To support his hypothesis he pointed out that several fossils of the oldest known bird, archaeopteryx, lack feathers.

Whether or not the new specimen raises interesting questions about how feathers -- and thus birds -- evolved, most experts do not see it as a challenge to the widely accepted view that modern birds are descended from dinosaurs.

NEW YORK – A beautifully preserved fossil from southern Germany raises questions about how feathers evolved from dinosaurs to birds, two paleontologists argue in a study published Thursday.

The 150 million-year-old fossil is a juvenile carnivorous dinosaur about 2½ feet long that scientists named Juravenator, for the Jura mountains where it was found.

It would have looked similar in life to the fleet-footed predators that menaced a young girl on the beach during the opening scene of “The Lost World,” the second Jurassic Park movie.

The fossil's exceptionally well-preserved bone structure clearly puts it among feathered kin on the dinosaur family tree. Because all of its close relatives are feathered, paleontologists would expect Juravenator to follow suit.

But a small patch of skin on the creature's tail shows no sign of feathers. And the skin also doesn't have the follicles that are typical of feathered dinosaurs, said Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles County. He and Ursula B. Gohlich of the University of Munich describe the fossil in Thursday's issue of the journal Nature.
 

“It has a typical scaly dinosaurian skin,” Chiappe said.

The paleontologists believe Juravenator's closest known relative may have been a fully feathered dinosaur from China, Sinosauropterix.

There are a number of possible explanations for Juravenator's nakedness. Feathers could have been lost on the evolutionary line leading to Juravenator after arising in an ancestor to both it and its feathered relatives. Or feathers could have evolved more than once in dinosaurs, cropping up in sister species at different times and places. It is also possible that this particular fossil of Juravenator, which appears to be a juvenile, only grew feathers as an adult or lost its feathers for part of the year.

But there is another possibility as well, said Mark Norell, curator of paleontology at the American Museum of Natural History: It is entirely possible that Juravenator did have feathers, but they simply failed to fossilize.

“Feathers are really just difficult things to preserve,” Norell said.

To support his hypothesis he pointed out that several fossils of the oldest known bird, archaeopteryx, lack feathers.

Whether or not the new specimen raises interesting questions about how feathers – and thus birds – evolved, most experts do not see it as a challenge to the widely accepted view that modern birds are descended from dinosaurs.