Specimens of Archaeopteryx feather's earlier discovery, von Meyer made the London fossil the type specimen of the genus ("Archaeopteryx") and species ("lithographica"), establishing it as the exemplar of the species' features. Its discovery and subsequent descriptions, a mere handful of years after Darwin's "On the Origin of Species", fulfilled the hope of a truly transitional form in its then-unique amalgamation of bird and reptilian characters. The specimen is preserved on two counter slabs broken originally into four pieces. The main, overlaying slab contains most of the skeletal elements, while only impressions and a few bone fragments are visible on the counter slab. This
Specimens of Archaeopteryx skeleton of a feathered animal from the same lithographic shale deposits, which would later be known as the London specimen. Coincidentally, von Meyer proposed the name "Archaeopteryx lithographica" for the feather, but not for the skeleton. Therefore, the official name of the animal was originally linked to the single feather rather than any actual skeleton, and is formally considered the original holotype. Though 1860 is often the year named for the feather's discovery, there is no proof of this date, and some authors consider it more likely to have been found in 1861, as it seems reasonable that von Meyer's