The complete and well-preserved skeleton of a new feathered dinosaur from the Middle Jurassic discovered in Liaoning Province, China, changes some previous ideas about the origin and evolution of birds. Aurornis xui – from the Latin Aurora and the term Ornis , which means 'bird of dawn' – is the name with which they have baptized the oldest avian dinosaur found to date , according to a study published in Nature echoed by the agency Sync.
Scientists from the Royal Belgian Institute of Natural Sciences have analyzed the fossil remains of this reptile and, after comparing it with other avians, have confirmed that both the new Aurornis xui and the classic Archeopteryx belong to the Avialae group . In addition, the study places Troodontidae , another family of bird-like dinosaurs, as a sister group to the Avians. The authors also suggest that bird diversification took place in Asia during the late Middle Jurassic.
Until now, there was no consensus among paleontologists on the position of Archeopteryx , since according to the definition of bird that is chosen, this famous animal may or may not be a bird. But the comparison of Aurornis with Archeopteryx places both within the Avialae group. This group, defined by Gauthier in 1986, includes those species that are closer to birds than to the dinosaur Deinonychus . In this way, Aurornis would be the oldest avians, and Archeopteryx one of the oldest points of divergence within the group .
