The new species was identified using the Daiting Specimen, found in 1990. The specimen was owned privately until 2009, when palaeontologist Raimun Albersdoerfer bought it, making it available for study.
The 12 Archaeopteryx fossils are sufficiently diverse that some have proposed each is a different species. However, a more favored categorization puts the other 11 into two species: A. lithographica and A. siemensii. Aside from one particularly incomplete fossil and another that has been stolen, the Daiting Archaeopteryx has been the most poorly understood of the specimens. Not only was it unavailable for study for so long but many of its bones and teeth remain trapped in the stone in which it was found.
Kear and co-authors addressed this using synchrotron microtomography, a sort of X-ray analysis that produces 3D images, revealing even the unextracted parts in great detail. Among other things, this showed that A. albersdoerferi acquired a number of adult features while still a juvenile, something that does not seem to be the case for the earlier members of the genus.
After the initial shock with which the first Archaeopteryx was received, just two years after the publication of the Origin of the Species, doubts have set in as to whether this truly is the link between dinosaurs and birds.
Not only has recent work shown birds are living dinosaurs, but numerous other species that combine wings and feathers with teeth and claws have been found living in other parts of the world at a similar time. This has raised questions as to whether Archaeopteryx really are a transitional species or if they evolved along a similar path to the true ancestors of birds, before coming to an evolutionary dead end.