Middle Jurassic–Present, 175.6–0 Ma Possible Early Jurassic record
|Mounted A. fragilis skeleton cast, San Diego Natural History Museum|
|Keel-billed toucan perched on a branch|
Avetheropoda was named by Gregory S. Paul in 1988, and was first defined as a clade by Currie and Padian in 1997, to include Allosaurus, modern birds, and other animals descended from their most recent ancestor. In 1999, Paul Sereno named another group, Neotetanurae, for the clade containing Allosauroidea and Coelurosauria, and excluding other tetanurans such as megalosauroids, but this definition was published slightly later.