Xiaotingia
A cladistic analysis by Xu and his team showed that Xiaotingia formed a clade with Archaeopteryx, the Dromaeosauridae and the Troodontidae. This clade excludes other birds. They therefore (re)defined the concepts of Deinonychosauria and Avialae so Archaeopteryx and Xiaotingia belonged to the Deinonychosauria and Archaeopteryx no longer was an avian (bird). This led to popular reports that "Archaeopteryx is no longer a bird".