The fossil record of birds stretches back to the Late Jurassic (about 150 million years ago), where we find Archaeopteryx.
There are numerous fossils of birds which radiated out during the Cretaceous.
The Neornithes are not convincingly represented in the fossil record before the Cretaceous and so on fossil data alone it has been suggested that they did not radiate out until the after the K-T Boundary. There are Cenozoic fossil representatives for 134 of the 153 living bird families.
Below is a diagram showing the geological time periods, and the major events in bird evolution we can infer based on the fossil record.
Author: Robert Davis
Last updated: 21/11/05
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