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 Eras of Life
 Dinosaur Evolution
 Feathered Dinosaurs
 Tyrannosaurs

Ancestors

  Introduction
  Herrerasaurus
  Eoraptor
  Coelophysis
  Eustreptospondylus

Species  

  Albertosaurus
  Alectrosaurus
  Alioramus
  Daspletosaurus
  Dilong
  Eotyrannus
  Gorgosaurus
  Nanotyrannus
  Tarbosaurus
  Tyrannosaurus
  Other Tyrannosaurs

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Information

   Anatomy
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   Family Life
   Growth Rate
   Exhibits
 Weird Dinosaurs
 Prehistoric Sea Monsters
 Pterosaurs
 Sauropods

 

 

Introduction to Tyrannosaur Evolution

    Below are the images and information that appears in the inset titled "Tyrannosaur Ancestors" located in the upper left corner of the poster.  These species are early meat-eaters that later evolved into the tyrannosaurs.  Note their similarities to their famous descendents.  The are bipedal; they walk on their powerful hind legs and use their heavy tails to maintain balance.  Their forearms are short and comparatively weak.  All have small heads.  The massive heads of the tyrannosaurs will develop later.
   Their is a page devoted to each species, which provides more detail.  The primary purpose of this page is to show all of them together in chronological order.

Eoraptor
228 million years ago
Name Means: "Dawn Thief"
Pronounced: EE-o-rap-tor
Fossils found: Northwest Argentina, Madagascar
Eoraptor is one of the earliest dinosaurs and its success as a hunter helped determine the survival of the species. An almost complete skeleton was discover in 1993. It has increased science knowledge of how dinosaurs developed and evolved.  Eoraptor had the characteristics of later dinosaurs - serrated teeth, grasping hand, light hollow bones and a strong, light skull.  Unlike many later dinosaurs, it had five fingers.
Herrerasaurus
225 Million years ago
Name Means: "Herrera's Lizard"
Pronounced: huh-Rare-uh-Sore-us
Fossils found: San Juan Province, northwestern Argentina
This is one of  the oldest dinosaurs ever found and is one of the three found in South America that represent the earliest of form of meat-eating dinosaurs. Unlike later dinosaurs, it ate many things including lizards, amphibians and possibly insects.  Its teeth are more conical in shape than later or contemporary dinosaurs and they have serrations like later carnivores
Coelophysis
220 million years ago
Name Means: "Hollow Form"
Pronounced: SEE-low-FIE-sis
A very common little hunter of the Late Triassic, Coelophysis came in two forms "robust" and "gracile" which may represent the two genders.  Because it was so small Coelophysis probably traveled and hunted in herds.  It had a long flexible neck and tail and walked upright on its strong birdlike hind legs.  It front limbs ended in three clawed fingers that could grab and tear prey
Eustreptospondylus
161-159 million years ago
Name Means: "Well Reversed Spine"
Pronounced: u-Strep-toe-spon-Di-lus
Fossils found: Oxford, England
   
   
 
 
 
    
 

 

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