Currie and Zhao (1993:2079) and, independently, Sereno et al. (1994) were first to use the taxon Allosauroidea. Sereno (1997) identified Allosauroidea as stem-based, but did not provide a definition. Sereno (1998) gave a stem-based definition that includes closely related taxa rather than just allosaurids and sinraptorids. There are a number of well preserved forms, including genera such as Yangchuanosaurus, Monolophosaurus, and Cryolophosaurus, with close, yet, uncertain, affinities to Allosaurus and Sinraptor. In this case, a stem-based taxon is more useful to allow reference to the clade as a whole. If spinosaurids or some other tetanurine clade is repositioned within Neotetanurae and is more closely related to Allosaurus fragilis, then they would also be considered allosauroids.

Padian and Hutchinson (1997:6, fig. 1) provided a node-based definition for Allosauroidea (mislabeled in their figure as “Allosauridae” ), basing the definition on Allosaurus and Sinraptor. In place of Allosauroidea as used by Sereno (1997, 1998), Padian et al. (1999) and Holtz et al. (2004) used a stem-based Carnosauria.

Sereno and others have rejected the use of Carnosauria, as it has a long history as a traditional polyphyletic repository for a disparate array of large-bodied theropods (see Carnosauria). Gauthier (1986:9) tried to resuscitate Carnosauria as a clade, but he did not provide a phylogenetic definition and listed large-bodied taxa that now are recognized as having disparate relationships (including abelisaurids, allosaurids, and tyrannosaurids). Furthermore, because relationships among allosauroids (sensu Sereno) are poorly known, there is often no demonstrable difference in the taxonomic content of Allosauroidea and Carnosauria (sensu Padian et al. 1998). In a recent review (Holtz et al. 2004), for example, Allosauroidea is listed in a taxonomy within Carnosauria, but the supporting phylogeny shows a basal polytomy with no resolution of Allosauroide.

Given these considerations, it may be best to avoid retooling the taxon Carnosauria out of respect for its historical usage. Allosauroidea is best conceived as a stem-based taxon, the definition derived from a first-order revision of Sereno (1998).