Archaeopteryx, Coelosaur, and a modern bird

    Archaeopteryx, one of the first birds (middle & right), more closely resembles Compsognathus, an archosaurian Coelosaur (top) than it does a modern bird (bottom: a pigeon). The principle difference is the greatly extended forelimbs, which function as wings. Given the current recognition of birds as a distinct taxonomic class (Aves), Archaeopteryx is retrospectively included in that group. Regarded prospectively, Archaeopteryx would have been classified as a dinosaur. In fact, early fragmentary fossils of Archaeopteryx without feather imprints were classified as dinosaurs. [more on Early bird evolution]

Text material © 2005 by Steven M. Carr