Classification
Rahonavis has historically been the subject of some uncertainty as to its proper taxonomic position - whether it is a member of the clade Avialae (birds) or a closely related dromaeosaurid. The presence of quill knobs on its ulna (forearm bone) led initially to its inclusion as an avialan; however, the rest of the skeleton is rather typically dromaeosaurid in its attributes. Given the extremely close affinities between primitive birds and their dromaeosaurid cousins, along with the possibility that flight may have developed and been lost multiple times among these groups, it has been difficult to place Rahonavis firmly among or outside the birds.
Rahonavis could be a close relative to Archaeopteryx, as originally suggested by the describers, and thus a member of the clade Avialae, but while the pelvis shows adaptations to flight similar in function to those of Archaeopteryx, they seem to be independently derived.
Beginning in the early 2000s, a consensus emerged among most theropod researchers that Rahonavis was more closely related to deinonychosaurs than to avialans, and specifically was a member of the South American dromaeosaurid clade Unenlagiinae. A 2005 analysis by Makovicky and colleagues found Rahonavis to be closely related to the unenlagiines Unenlagia and Buitreraptor. Norell and colleagues (2006) also found Rahonavis to lie within the Unenlagiinae, as the sister taxon to Unenlagia itself. A 2007 study by Turner and colleagues again found it to be an unenlagiine dromaeosaurid, closely related to Unenlagia.
This consensus has been challenged, however, by a few studies published since 2009 that have found many traditional "dromaeosaurids", including the unenlagiines, closer to Avialae than to dromaeosaurines. A large analysis published by Agnolín and Novas in 2013, for example, recovered Rahonavis as closer to Avialae than to Dromaeosauridae. That study found Rahonavis in particular to be closer to birds than either unenlagiines or dromaeosaurids.
The discoverers of Rahonavis initially named it Rahona but changed the name after discovering that the name Rahona was already assigned to a genus of lymantriid moths.
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