TYPE SPECIES:
• A. lithographica von Meyer, 1861 sensu Nopcsa, 1927 [nomen conservandum] "stone-written ancient wing/feather"
  OTHER SPECIES:
• A. bavarica Wellnhofer, 1993 "Bavarian ancient wing/feather"
  
  MISASSIGNED SPECIES:
• A. crassipes (von Meyer, 1857) [nomen oblitum] (originally Pterodactylus) == Archaeopteryx lithographica
• A. macrura Owen, 1862 [nomen oblitum] "large-tailed ancient wing/feather" == A. lithographica
• A. oweni Petronievics, 1917 [nomen oblitum] "Sir Richard Owen's ancient wing/feather" == A. lithographica
• A. recurva Howgate, 1984 "recurved ancient wing/feather" ?= Archaeopteryx lithographica
• A. siemensii Dames, 1897 == A. lithographica

Animalia
Vertebrata
Tetrapoda
Sauropsida
Archosauromorpha
Ornithodira
Dinosauria
Theropoda
Tetanurae
Coelurosauria
Avialae

The origin of birds is associated with this creature, the "first bird" (nicknamed "Archie"). Although it resembled other small theropods so much that one skeleton was for years mistakenly identified as Compsognathus, it bore feathers identical to those of modern flying birds. When it was first discovered in 1861, early evolutionists quickly recognized it as the "missing link" between birds and more primitive reptiles.

In many ways, Archaeopteryx was unlike modern birds. Like non-avian dinosaurs, it had a bony tail (short for a theropod, very long for a bird), teeth, and clawed fingers. It also had a hyperextendable "switchblade" claw on each foot, like its relatives the dromaeosaurids. But it was a bird and featured avian characteristics, like a reduced number of tail vertebrae and unserrated teeth.

Here is a table of known Archaeopteryx specimens (which are named after where they were first displayed):

Specimen    Found Recognized Complete
(feather)   1860
London      1861
Berlin      1876             X
Maxberg     1956
Haarlem     1855  1970
Eichstätt   1951  1970       X
Solnhofen         1987       X
A. bavarica 1992  1993       X

The Solnhofen specimen may represent a new genus and species, Wellnhoferia grandis.