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 "Archaeopteryx" likely indicated it had very little flight ability. The furcula (wishbone) is well-preserved and lies between the scapulae; its boomerang-like shape reveals a 75-degree angle between its branches. De Beer identified a compressed mass of bone as a sternum in the London specimen, but later researchers disputed this as more likely to be a concretion of vertebrae encrusted by calcite. That "Archaeopteryx" lacked a bony sternum is in agreement with the modern consensus that many specimens of "Archaeopteryx", including the London, likely represented immature animals whose sterna were still cartilaginous. The pelvic girdle is separated into its three components