Allosauroid

Classification

Within Carnosauria, there is a slightly more exclusive clade, superfamily Allosauroidea. The clade Allosauroidea was originally named by Othniel Charles Marsh, but it was given a formal definition by Phil Currie and Zhao, and later used as a stem-based taxon by Paul Sereno in 1997. Sereno was the first to provide a stem-based definition for the Allosauroidea in 1998, defining the clade as "All neotetanurans closer to Allosaurus than to Neornithes." Kevin Padian used a node-based definition in his 2007 study which defined the Allosauroidea as Allosaurus, Sinraptor, their most recent common ancestor, and all of its descendants. Thomas R. Holtz and colleagues and Phil Currie and Ken Carpenter, among others, have followed this node-based definition. Depending on the study, Carnosauria and Allosauroidea are sometimes considered synonymous. In such cases, several researchers have elected to use Allosauroidea over Carnosauria.