Archaeopteryx.
Archaeopteryx is a genus of bird-like dinosaurs considered to represent part of the transition from non-avian feathered dinosaurs to contemporary birds. The name come from the ancient Greek and means “feather” or “wing”. Around the turn of the 19th and 20th centuries, Archaeopteryx had been known by palaeontologists and many reference books as the oldest known bird (member of the Avialae group). However, older potential avialans were identified subsequently, including Anchiornis, Aurornis and Xiaotingia.