Paravians

Paravians are a clade of theropod dinosaurs within Coelurosauria that includes birds (Avialae) and their closest non-avian relatives, the dromaeosaurids and troodontids. In phylogenetic usage, Paravians form a subset of Paraves, defined by evolutionary relationships rather than a single diagnostic trait. They are united by the evolutionary development of flight-related anatomy, including an elongated forelimb and a specialized wrist, as well as evidence of extensive feathering.

Fossils show feathers in both avialans and non-avian paravians, indicating that feathering predates powered flight. Notable paravians include Archaeopteryx (an early bird), Velociraptor and Deinonychus (dromaeosaurids), and Troodon (a troodontid). Together with other paravians, they illustrate the evolutionary transition from feathered dinosaurs to birds and reveal a mosaic of avian and non-avian features in the lineage.

Temporal and geographic range: Paravians first appear in the Jurassic and become diverse in the Cretaceous, with fossils found on multiple continents. The lineage ultimately yields the modern birds, the only living paravians. The study of paravians supports the view that birds are part of the theropod dinosaur lineage rather than a separate origin of flight.

See also: Paraves, Deinonychosauria, Avialae, Dromaeosauridae, Troodontidae.