Archaeopteryx lithographica Only five specimens of this species, the first bird, are known. Archaeopteryx is recorded solely from the Lithographic Limestone of the Solnhofen region of Bavaria, Germany. It was first described by H. von Meyer in 1861 and is of Middle Kimmeridgian or Upper Jurassic age. Recent work on this species by several palaeontologists tends to support the theory that the birds, through Archaeopteryx, evolved from coelurosaur dinosaurs similar to Compsognathus. The species A. lithographica possesses several primitive characters such as teeth, as well as specialized features such as feathers and hollow bones. It is a good example of a connecting species which exhibits a mosaic of evolutionary features.

Archaeopteryx lithographica The first known bird, of which only six specimens and one feather imprint have been found, all of them from the Lithographic Limestone of the Solnhofen region of Bavaria, Germany. The bird was first described by H. von Meyer in 1861 and is of Middle Kimmeridgian (Upper Jurassic) age. Work by several palaeontologists tends to support the theory that the birds, through Archaeopteryx, evolved from coelurosaur dinosaurs (Coelurosauria) similar to Compsognathus. The species A. lithographica possesses several primitive characters such as teeth, as well as specialized features such as feathers and hollow bones. It is a good example of a connecting species which exhibits a mosaic of evolutionary features.

archaeopteryx First known bird. About the size of a crow and fully feathered, its fossilized skeleton is more like that of a reptile than a modern bird, and its beak had pronounced jaws with teeth. It was capable probably only of weak flight.

http://www.ucmp.berkeley.edu/diapsids/birds/archaeopteryx.html