Archaeopteryx, the earliest known bird, now extinct. It lived about 150 million years ago. The archaeopteryx was about the size of a small crow. It had short wings; each wing had three clawed digits. Its feet were adapted to climbing trees and perching on branches. It had many of the characteristics of a reptile, including toothed jaws and a long, bony tail.

Most fossils of the archaeopteryx show no evidence of a breastbone, the bone to which wing muscles are attached in modern birds. Some scientists believe these fossils indicate that the archaeopteryx lacked a breastbone and was a poor flier, capable of doing little more than gliding. However, other scientists believe the archaeopteryx had a breastbone, but that the breastbone was not preserved in these fossils. An archaeopteryx fossil discovered in 1992 shows evidence of a breastbone, indicating that at least some archaeopteryxes may have been capable of sustained flight.

Fossils of archaeopteryx skeletons and feathers were first discovered in 1861, in a limestone quarry in Solnhofen, Bavaria.

The archaeopteryx was Archaeopteryx lithographica. Scientists who believe that A. lithographica did not have a breastbone generally recognize a second species, A. bavarica, which did have one.

Bird subtitle Evolution of Birds.