Transitional fossil that share a more recent common ancestor with one another than they do with other groups. There are a few exceptional cases, such as some marine plankton microfossils, where the fossil record is complete enough to suggest with confidence that certain fossils represent a population that was actually ancestral to a later population of a different species. But, in general, transitional fossils are considered to have features that illustrate the transitional anatomical features of actual common ancestors of different taxa, rather than to "be" actual ancestors. "Archaeopteryx" is a genus of theropod dinosaur closely related to the birds. Since the
Specimens of Archaeopteryx the feather. "Archaeopteryx lithographica" was initially named for this original feather, rather than the full skeleton that was found around the same time, and the feather was originally the formal type specimen and holotype for the species. There are obvious problems with this idea, such as the fact that the feather may have come from a juvenile, or possibly another species altogether. The distal obtuse angle at the tip is not a feature found on the feathers of any other "Archaeopteryx" skeleton with integument imprints. It is possible, however, that the strange angle of the tip is an artifact caused