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Subclade Archosauria: Avemetatarsalia to Neornithes 

Taxon Feedback
Taxon Tyrannosauroidea 
Nominal Author Osborn 1906 
2° Nominal Author Walker 1964 
Taxon Status active

Bonaparte et al. (1990) indicated their first used Tyrannosauroidea and were credited accordingly by Sereno (1998). Walker (1964), however, was first to use the superfamily in his classification that included the families Ornithosuchidae, Tyrannosauridae, and Spinosauridae.

Tyrannosauroidea was first defined by Sereno (1998) as a stem-based definition to include all members of this increasingly diverse stem clade. Sereno (1998) only used Neornithes as an external specifier. Holtz (2004) use Ornithomimus velox, Deinonychus antirrhopus, and Allosaurus fragilis. The critical external specifiers are those that represent clades that could conceivable be related to tyrannosauroids, and these include ornithomimosaurs, troodontids, and dromaeosaurids. There is really no need to include Allosaurus or Passer as external specifiers, as no recent cladogram considers Aves or Allosauroidea close relatives of tyrannosauroids. The active definition is a first-order revision of both previous definitions (Sereno 1998, Holtz 2004).

Potential Synonomy  

Active Phylogenetic Definition Feedback
Active Definition The most inclusive clade containing Tyrannosaurus rex Osborn 1905 but not Ornithomimus edmontonicus Sternberg 1933, Troodon formosus Leidy 1856, Velociraptor mongoliensis Osborn 192). 
Shorthand > Tyrannosaurus rex but not Ornithomimus edmontonicus, Therizinosaurus cheloniformis,Shuvuuia deserti, Oviraptor philoceratops, Troodon form 
Definitional Author Sereno 2005 
Definition Status original
textual substitution
first-order revision
second-order revision
Definition Type node
Node-Stem Triplet yes
Other Triplet Taxa  
Specifier A Tyrannosaurus rex 
Specifier(s) B  
Specifier(s) C Ornithomimus edmontonicus, Troodon formosus, Velociraptor mongoliensis 
Taxonomic Content stem (entirely extinct)
crown (extant-bounded)
mixed (extant/extinct-bounded)
Publication Year 1998 

Inactive Taxon Status Feedback
Rejection Criteria junior synonym
historically polyphyletic
incomplete definition
no definition

Current Age Range Feedback
Earliest Record Kimmeridgian-Tithonian (151 Ma) 
Latest Record Maastrichtian (66 Ma) 
Range (My) 85 
Basis for Range The earliest tyrannosauroid is Stoksosaurus clevlandi from the Kimmeridgian-Tithonian Morrison Formation. The latest records come from both Asia and North America from Maastrichtian-age formations (Holtz 2004). Dates are rounded to the nearest million, the earliest from the Kimmeridgian-Tithonian boundary and the latest from the end of the stage (Gradstein et al. 2004). 

Definitional History #1
Definition 1 All maniraptorans closer to Tyrannosaurus than to Neornithes. 
Author Sereno 1998:65 
Type node  stem 
Specifiers Tyrannosaurus, Neornithes 

Definitional History #2
Definition 2 Tyrannosaurus rex and all taxa sharing a more recent common ancestor with T. rex than with Ornithomimus velox, Deinonychus antirrhopus, or Allosaurus fragilis
Author Holtz 2004:114 
Type node  stem 
Specifiers Tyrannosaurus rex, Ornithomimus velox, Deinonychus antirrhopus, Allosaurus fragilis