Maniraptorans are characterized by long arms and three-fingered hands (though reduced or fused in some lineages), as well as a "half-moon shaped" (semi-lunate) bone in the wrist (carpus).

More primitive maniraptorans, such as therizinosaurs (specifically Beipiaosaurus), preserve a combination of simple downy filaments and unique elongated quills.

[5][6] Simple feathers are known from more primitive coelurosaurs such as Sinosauropteryx prima, and possibly from even more distantly related species such as the ornithischian Tianyulong confuciusi and the flying pterosaurs.

Powered and/or gliding flight is believed to have been present in some types of non-avialan paravians, including dromaeosaurids, such as Rahonavis and Microraptor.

[9] The Maniraptora was originally named by Jacques Gauthier in 1986, for a branch-based clade defined as all dinosaurs closer to modern birds than to the ornithomimids.

In 1993, Perle and colleagues coined the name Metornithes to include alvarezsaurids and modern birds, which the researchers believed were members of the Avialae.

[12] Pennaraptora (Latin penna "bird feather" + raptor "thief", from rapere "snatch"; a feathered bird-like predator) is a clade within Maniraptora, defined as the most recent common ancestor of Oviraptor philoceratops, Deinonychus antirrhopus, and Passer domesticus (the house sparrow), and all descendants thereof, by Foth et al., 2014.

[16] †Alvarezsauroidea †Therizinosauridae †Oviraptorosauria †Dromaeosauridae †Troodontidae Avialae In 2002, Czerkas and Yuan reported that some maniraptoran traits, such as a long, backwards-pointed pubis and short ischia were present in Scansoriopteryx, a scansoriopterygid.

[18] Scientists traditionally assumed that maniraptorans were ancestrally hypercarnivorous, that is, that most non-avialan species primarily ate and hunted only other vertebrates.

Additionally, phylogenetic studies of maniraptoran relationships began to more consistently show that herbivorous or omnivorous groups were spread throughout the Maniraptora, rather than representing a single side-branch as previously thought.