forward-pointing teeth, and the 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. In 2007, a review of all well-preserved specimens including the then-newly discovered Thermopolis specimen concluded that two distinct species of Archaeopteryx could be supported: A. lithographica (consisting of at least the London and Solnhofen specimens), and A. siemensii (consisting of at least the Berlin, Munich, and Thermopolis specimens). The two species are distinguished primarily by large flexor tubercles on the foot claws in A. lithographica (the claws of A. siemensii specimens being relatively simple and straight). A. lithographica also had a constricted portion of the crown in some teeth and a stouter metatarsus. A supposed additional species, Wellnhoferia grandis (based on the Solnhofen specimen), seems to be indistinguishable from A. lithographica except in its larger size. Synonyms If two names are given, the first denotes the original describer of the "species", the second the author on whom the given name combination is based. As always in zoological nomenclature, putting an author's name in parentheses denotes that the taxon was originally described in a different genus. Archaeopteryx lithographica Meyer, 1861 [conserved name] Archaeopterix lithographica Anon., 1861 [lapsus] Griphosaurus problematicus Wagner, 1862 [rejected name 1961 per ICZN Opinion 607] Griphornis longicaudatus Owen vide Woodward, 1862 [rejected name 1961 per ICZN Opinion 607] Archaeopteryx macrura Owen, 1862 [rejected name 1961 per ICZN Opinion 607] Archaeopteryx oweni Petronievics, 1917 [rejected name 1961 per ICZN Opinion 607] Archaeopteryx recurva Howgate, 1984 Jurapteryx recurva (Howgate, 1984) Howgate, 1985 Wellnhoferia grandis Elżanowski, 2001 Archaeopteryx siemensii Dames, 1897Archaeornis siemensii (Dames, 1897) Petronievics, 1917 Archaeopteryx bavarica Wellnhofer, 1993"Archaeopteryx" vicensensis (Anon. fide Lambrecht, 1933) is a nomen nudum for what appears to be an undescribed pterosaur. Phylogenetic position Modern palaeontology has often classified Archaeopteryx as the most primitive bird. However, it is not thought to be a true ancestor of modern birds, but rather a close relative of that ancestor. Nonetheless, Archaeopteryx was often used as a model of the true ancestral bird. Several authors have done so. Lowe (1935) and Thulborn (1984) questioned whether Archaeopteryx truly was the first bird. They suggested that Archaeopteryx was a dinosaur that was no more closely related