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 Eras of Life
 Dinosaur Evolution
 Feathered Dinosaurs

Species

 Compsognathidae

MYA
   Compsognathus

150

   Sinosauropteryx

130

 Therizinosauroidea
   Beipiaosaurus

130

   Falcarius

125

   Alxasaurus

112

   Erlikosaurus

95

   Therizinosaurus

75

 Oviraptoridae
   Caudipteryx

140

   Insicivosaurus

120

   Avimimus

95

   Chirostenotes

70

   Rinchenia

70

   Nomingia

68

   Oviraptor

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

 Tyrannosaurs
 Weird Dinosaurs
 Prehistoric Sea Monsters
 Pterosaurs
 Sauropods

 

 

Troodontidae

   The troodontids are best characterized as small, rather delicate theropods with relatively the largest brains of any classic dinosaur, long and slender legs, and unusual teeth that have been mistaken for those of the ornithischian group Pachycephalosauria.  These teeth have led some researchers to suggest that they were omnivorous.  Like ornithomimosauroids, they had large eyes.  Troodontidae has proven hard to classify, and can be linked by various characteristics with Spinosauridae, Dromaeosauridae, Oviraptorosauria, and Ornithomimosauria.  In the recent past, they were often combined with the ornithomimosaurians into a taxon called Bullatosauria, meaning "inflated reptiles" (referring to a "swollen" bone in the braincase).  Part of the difficulty is that they are still rather poorly known; only one really complete skeleton, that attributed to Sinornithoides, has been uncovered.  In addition, until recently there had been no good basal troodontid remains known, hindering comparisons.  With the discovery of Sinovenator, however, Troodontidae seems to mesh with Dromaeosauridae in Deinonychosauria, just as in the early 1980s. 
    For a long time, this family was known as Saurornithoididae, because Troodon was thought to be a dubious pachycephalosaurid.  It may return to this name if recent investigations into Troodon show that the type teeth are not "troodontid".

Sinornithoides youngi - 110 MYA
Mongolia, China.  3.5 feet long
The first dinosaur discovered with primitive feathers.
Troodon Formosus - 67 MYA
Montana, USA; Alberta, Canada. - 6 feet long.
The "type" species.

Mei long - 130 MYA
Liaoning Province, China - 21 inches long
This 2004 discovery is remarkable because its forelimbs are folded birdlike next to its body
 

Other Species

  The Troodontidae are very rare in the fossil record.  Only nine species are known.  They include:
  Saurornithoides mongoliensis (Late Cretaceous, Mongolia)
  Borogovia gracilicrus (Late Cretaceous, Mongolia)
  Sinovenator changii [sic] (Early Cretaceous, China)
  Byronosaurus jaffei (Late Cretaceous, Mongolia)
  Sinusonasus magnodens (Early Cretaceous, China)
  Mei long (Early Cretaceous, China)
"
soundly sleeping dragon"
 is a duck-sized species of dinosaur first unearth by paleontologists in Liaoning, China in 2004. Some of the unearthed fossils from the site, preserved in three-dimensional detail, were found with their faces nestled behind one of their forelimbs, similar to a sleeping position ducks sometimes posture. The fossil provides a possible behavioral link between birds and dinosaurs.

 

   
   
 
 
 
 
 

 

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