Dinosaurs | Egypt | Mesopotamia |Human Ancestors
The great dinosaurs roamed the Earth during the Mesozoic Era from 225 to 65 million years ago at which point a mass extinction took place leaving the only surviving dinosaurs, birds. This website provides background information on all the major dinosaur groupings, and has specific information on a typical representative of each major grouping.
What are Dinosaurs?
Dinosaurs belong to a larger group of animals called the archosaurs. They differ
from the other archosaurs in that the joint between the leg and the hip forms
a complete hole. The archosaurs, like their relatives the lepidosaurs, are
diapsids. The diapsids are grouped with the anapsids, parapsids, and syanpsids in the grouping called Amniota -- animals that have watertight eggs.
What are the Major Types of Dinosaur?
The Dinosauria (the scientific name for the grouping of animals that are dinosaurs)
are subdivided into two major groupings, the Saurischia (lizard hipped) and
the Ornithischia (bird hipped).
Oddly,
Saurischian dinosaurs are the ancestors of extant birds, while the
Ornithischians are now all extinct. The Saurischia includes all the meat-eating
dinosaurs like Tyrannosaurus, as well as all the giant Sauropods like Apatosaurus.
A List of Included Dinosaurs
Selecting a species below will bring you to the page about that particular
animal.
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