T Rex

When did the dinosaurs first appear on Earth?

The oldest dinosaur types are known from rocks in Argentina and Brazil and are about 230 million years old. The most primitive of these types, Eoraptor, was a small meat-eating dinosaur. Because Eoraptor's skeleton shows some advanced skeletal features, older dinosaurs may yet be found.

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This page is URL:http://pubs.usgs.gov/gip/dinosaurs/when.html
For more information, please contact Robert Weems at rweems@usgs.gov or Ronald Litwin at rlitwin@usgs.gov.

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Last modified 05-17-01 (krw)