Avetheropoda

Avetheropoda is a clade of theropod dinosaurs within the larger group Theropoda, situated among the Tetanurae. It was defined phylogenetically as the most inclusive clade containing Allosaurus fragilis and birds (Aves) but excluding Ceratosaurus nasicornis. In practical terms, Avetheropoda encompasses theropods that are more closely related to birds than to Ceratosaurus, serving as a backbone for several later theropod lineages.

The composition of Avetheropoda is widely treated as consisting of two major lineages: Allosauroidea and Coelurosauria. Allosauroidea includes large predatory theropods such as Allosaurus and related carcharodontosaurids, whereas Coelurosauria includes tyrannosauroids, ornithomimosaurs, and the diverse group of maniraptorans, among others. Birds are the living crown group within Avetheropoda, representing the most derived coelurosaurian lineage.

The fossil record of Avetheropoda extends from the Middle Jurassic through the Late Cretaceous, with the clade continuing today in the form of birds. As a clade, Avetheropoda has been the subject of ongoing phylogenetic research, and its precise internal arrangement varies among analyses. Nevertheless, it serves as a major framework for understanding the evolution of many well-known theropod groups, from the historically dominant apex predators of the Jurassic and Cretaceous to the origin and diversification of birds.

See also: theropod evolution, Coelurosauria, Allosauroidea, Tyrannosauroidea, Maniraptoriformes.