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Species

 Compsognathidae

MYA
   Compsognathus

150

   Sinosauropteryx

130

 Therizinosauroidea
   Beipiaosaurus

130

   Falcarius

125

   Alxasaurus

112

   Erlikosaurus

95

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75

 Oviraptoridae
   Caudipteryx

140

   Insicivosaurus

120

   Avimimus

95

   Chirostenotes

70

   Rinchenia

70

   Nomingia

68

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67

 Dromaeosauridae
   Microraptor

126

   Deinonychus

120

   Buitreraptor

90

   Unenlagia

90

   Bambiraptor

80

   Atrociraptor

70

   Dromaeosaurus

70

   Velociraptor

67

 Tyrannosauridae
   Dilong

130

 Troodontidae
   Mei long

130

   Sinornithoides

105

   Troodon

 67

 Alvarezsauridae
  Patagonykus 95
  Shuvuuia 80
  Alvarezsaurus 80
  Parvicursor 80
  Mononykus 70
 Aves (birds)
   Protarchaeopteryx

135

   Archaeopteryx

147

  Recent Discoveries
  Juraventor Starki

Information

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Atrociraptor marshalli  (Currie, 2004)


    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.

Name Means: "Marshall's Cruel Thief" Length:
Pronounced:   Weight:  
When it lived: 70 MYA    
Where found: Alberta, Canada    

    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.

 

 
 
Juraventor Starki
Name Means: Length:
Pronounced:   Weight:  
When it lived:      
Where found:      
     Berlin, Germany (RCN) - the fossil better preserved of saurio predator, that lived 150 million ago years, was discovered in a deposit of the locality of Schamhaupten, to the south of Germany, in the region of Baviera.

The Juraventor Starki, that means "Cazador Jurásico", has the size of ganso and is part of the family of the coelosaurios. This species was fed on the meat of smaller organisms.

According to the article about the discovery, published by the magazine "Nature", the paleontóloga Ursula Goehlich, one of the people in charge of the finding, indicated that the animal of about 75 centimeters was found in its totality, with the exception of the last third of the tail.

Also vestiges of the skin of dinosaurio were found, which has allowed to determine that the animal lacked pens, as they had many of his contemporary ones.

The experts sustain that this fossil is an attempt of which the adoption of pens on the part of the dinosaurios that do not consider birds, corresponds to a much more complex process of the imagined one by the paleontólogos.
 

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 2˝ 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.

As I mentioned in in my last entry, the latest issue of Nature includes the description of a new theropod dinosaur from the Late Jurassic Solnhofen Limestone of Germany. Like most vertebrate finds made in the Solnhofen, the same geological formation which has preserved Archaeopteryx lithographica, the holotype of Juravenator starki is a spectacularly beautiful and well-preserved fossil (Jura = after the Bavarian Jura Mountains venator, Latin, meaning "hunter'; the species name honours the quarry owners). It's been placed in the Compsognathidae, along with the genera Compsognathus (also from the Solnhofen), Sinosauropteryx and Huaxiagnathus (both from China). Juravenator starki is the most complete non-avian theropod known from anywhere in Europe. And it's a tiny beast, just a little more than two feet from the end of the snout to the tip of its slender tail, but as this specimen is clearly a juvenile, the size of an adult Juraventor remains unknown. Unlike many (if not most) other theropods, Juraventor appears to have lacked feathers:
 

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 2˝ 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.

 

 

Name Means: Length:
Pronounced:   Weight:  
When it lived:      
Where found:      

  

 
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