Gauthier coined and defined Tetnaurae as a stem-based taxon to include all theropods closer to birds than to Ceratosauria, a clade that has since been separated into two clades (Coelophysoidea, Ceratosauria sensu stricto; Wilson et al. 2003). Novas (1992) acknowledged Gauthier’s definition but then, without explanation, redefined Tetanurae as a node-based group for a less inclusive clade. Holtz (1994) and Hutchinson and Padian (1997) used Gauthier’s definition, and Sereno listed Tetanurae as a stem-based taxon, consistent with Gauthier (1986).
Sereno (1998) and Padian et al. (1999) altered “birds” to Neornithes (crown-group birds). Sereno (1998:64) accidentally used an ingroup genus, Torvosaurus, as an external specifier (which clearly contradicted the position of Tetanurae on an associated cladogram), wheras Padian et al. (1999) used Ceratosaurus. Wilson et al. (2003) clarified Sereno’s error, replacing Torvosaurus with Ceratosaurus nasicornis. Although Ceratosaurus is not nested within Ceratosauria, it is the eponymous taxon and it was thought best not to introduce yet another specifier or alternative taxon, a consideration discussed by Wilson et al. (2003).
The active definiton is a first-order revision of that in Wilson et al. (2003) that replaces Neornithes with Passer domesticus and adds one additional, nested species, Carnotaurus sastrei, to ensure the stability of the taxonomic content of Tetanurae.