Paraves

Paraves is a branch-based clade defined to include all dinosaurs which are more closely related to birds than to oviraptorosaurs. Paravians comprises two major sub-groups: Avialae, including Jeholornis and flying birds, and Deinonychosauria, which includes the dromaeosaurids and troodontids.

The ancestral paravian is a hypothetical animal; the first common ancestor of birds, dromaeosaurids, and troodontids which was not also ancestral to oviraptorosaurs. Little can be said with certainty about this animal. The work of Turner et al. (2007) suggested that the ancestral paravian could not glide or fly, and that it was most likely small (around 65 centimeters long and 600–700 grams in mass). But the work of Xu et al. (2003), (2005) and Hu et al. (2009) provide examples of basal and early paravians with four wings, including members of the Avialae (Pedopenna), Dromaeosauridae (Microraptor), and Troodontidae (Anchiornis).

Classification
The name Paraves was coined by Paul Sereno in 1997. The clade was defined by Sereno in 1998 as a branch-based clade containing all Maniraptora closer to Neornithes (which includes all the birds living in the world today) than to Oviraptor.

Also in 1997, a node-based clade called Eumaniraptora ("true maniraptorans") was named by Padian, Hutchinson and Holtz. They defined their clade to include only birds and deinonychosaurs. However, because there are currently no known species of paravian which are not also eumaniraptoran, these groups are considered to be synonyms.

The cladogram presented below follows a study by Zhang et al. 2008.

A 2011 report on the discovery of a new Archaeopteryx-like theropod Xiaotingia zhengi suggests that including it in a cladistic analysis shifts Archaeopteryx and similar species from the Avialae into the Deinonychosauria. Statistical support for the hypothesis is limited, and the authors say that it needs to be confirmed by further investigation.