Ancient Cousins of Dinosaur
Alondra S.

Around 65 million years ago an asteriod crashed into earth and caused a mass extincintion of most prehistoric life on earth. One dinosaur-like animal managed to survive the extinction and is still alive today.

Evolution of a Mighty Lizard

Archosaur Family ( Ruling Lizards )

  • Emerged about 250 million years ago during the late Permian period.
  • Dominant during Cretaceous ( Age of the Reptiles) period.
  • Around 220 million years ago ( late Triassic period ) they divided into 2 evolotionary lines.

Distant Ancestors

Geosaurs - lived late Jurassic , early Cretachous period. Aquatic reptile grew up to 10 feet (3m)

Leidysuchus - Fossils found in the north america lived during the Cretachous period.

Deinosuchus - known as " Terrible Crocodile " largest crocodilian, lived during the late creteceous period.


In general early Archosaurs resemble modern day crocodiles. They have simliar pyshical features such as narrow skulls, pointed snouts, teeth set in sockets and modified ankle joint.

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