Archaeopteryx (är´kēŏp´tərĬks) [Gr.,=primitive wing], a 150 million-year-old fossil animal first discovered in 1860 in the late Jurassic limestone of Solnhofen, Bavaria, and described the following year. All eight known fossils of Archaeopteryx, discovered between 1860 and 1992, were found in a 516 sq-mi (1,336 sq-km) area of the Solnhofen quarries. First classified as a bird because of the presence of feathers and the structure of the legs and wings, it nevertheless has many characteristics now found only in reptiles or in bird embryos. It was long regarded as the most primitive known bird, but more recent discoveries of fossils that have feathers and other birdlike features while also retaining strong dinosaurlike characteristics has led some to argue that Archaeopteryx is in fact a feathered dinosaur that should be grouped with the theropods. It is still debated whether Archaeopteryx, which was about the size of a pigeon or grackle, was arboreal or a swiftly running terrestrial animal and poor flyer; its feathers appear to have been too weakly constructed to be useful for active flight. Some claimed that a fossil discovered in West Texas in 1983 and dubbed Protoavis represents a primitive bird that predated Archaeopteryx by some 75 million years, but many experts also have questioned whether Protoavis is in fact a bird or even an correctly reconstructed animal.
See L. M. Witmer, The Search for the Origin of Birds (1995); A. Feduccia, The Origin and Evolution of Birds (1996); S. Chatterjee, The Rise of Birds (1997); P. Shipman, Taking Flight: Archaeopteryx and the Evolution of Bird Flight (1998).