Archaeopteryx (if not colour banded) to some degree, so the darkness was attributed to such impurities. They also mention that a complete absence of air bubbles in the rock slabs is further proof that the specimen is authentic. Modern paleontology has often classified "Archaeopteryx" as the most primitive bird. 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
Specimens of Archaeopteryx that "Archaeopteryx" could have raised its short second toe in a similar manner to its dromaeosaur cousin "Deinonychus", whose second toe bore an enlarged "sickle claw" for probable use in predation. It remains unclear whether "Archaeopteryx" also used its hyperextended toe-claw in a similar fashion or for some other purpose. Taken together, many of the unique features of the skull, feet and coracoid strengthen a close relationship of archaeopterygids to deinonychosaurian theropods. Well-preserved imprints of wing and tail plumage show details of the barbs, but not barbules, and the shafts of 11 primaries can be counted on the right wing.