 It has been argued that all the specimens belong to the same species, A. lithographica. Differences do exist among the specimens, and while some researchers regard these as due to the different ages of the specimens, some may be related to actual species diversity. In particular, the Munich, Eichstätt, Solnhofen, and Thermopolis specimens differ from the London, Berlin, and Haarlem specimens in being smaller or much larger, having different finger proportions, having more slender snouts lined with forward-pointing teeth, and possible presence of a sternum. Due to these differences, most individual specimens have been given their own species name at one point or another. The Berlin specimen has been designated as Archaeornis siemensii, the Eichstätt specimen as Jurapteryx recurva, the Munich specimen as Archaeopteryx bavarica, and the Solnhofen specimen as Wellnhoferia grandis.
