Archaeopteryx for flightless birds. In 2010, Robert L. Nudds and Gareth J. Dyke in the journal "Science" published a paper in which they analysed the rachises of the primary feathers of "Confuciusornis" and "Archaeopteryx". The analysis suggested that the rachises on these two genera were thinner and weaker than those of modern birds relative to body mass. The authors determined that "Archaeopteryx" and "Confuciusornis", were unable to use flapping flight. This study was criticized by Philip J. Currie and Luis Chiappe. Chiappe suggested that it is difficult to measure the rachises of fossilized feathers, and Currie speculated that "Archaeopteryx" and "Confuciusornis"
Archaeopteryx common uses of that term. A more thorough analysis was published soon after to test this hypothesis, and failed to arrive at the same result; it found "Archaeopteryx" in its traditional position at the base of Avialae, while "Xiaotingia" was recovered as a basal dromaeosaurid or troodontid. The authors of the follow-up study noted that uncertainties still exist, and that it may not be possible to state confidently whether or not "Archaeopteryx" is a member of Avialae or not, barring new and better specimens of relevant species. Phylogenetic studies conducted by Senter, "et al." (2012) and Turner, Makovicky, and Norell