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Clade
Subclade Archosauria: Avemetatarsalia to Neornithes 
Taxon Feedback
Taxon Alvarezsauridae 
Nominal Author Bonaparte 1991 
2° Nominal Author  
Taxon Status active
inactive
Comments The active definition is a first-order revision of the first phylogenetic definition given by Sereno (1999b). It is stem-based like the original but is not affected by any of the postulated immediate sister taxa--including avians. Shuvuuia deserti was chosen as the internal specifier because it is well known and nested among alvarezsaurid. By comparison, the eponymous species Alvarezsaurus calvoi (Chiappe et al. 2002) is poorly known although clearly related. This nominotypical species could be included as a positive taxon qualifier, although the definition is presented without its inclusion here because of its clear relationship with Shuvuuia. 
Potential Synonomy  
Active Phylogenetic Definition Feedback
Active Definition The most inclusive clade containing Shuvuuia deserti Chiappe et al. 1998 but not Ornithomimus edmontonicus Sternberg 1933, Tyrannosaurus rex Osborn 1905, Therizinosaurus cheloniformis Maleev 1954, Oviraptor philoceratops Osborn 1924, Troodon formosus Leidy 1856, Passer domesticus (Linnaeus 1758). 
Shorthand > Shuvuuia deserti but not Ornithomimus edmontonicus, Tyrannosaurus rex, Therizinosaurus cheloniformis, Oviraptor philoceratops, Troodon formosus, Passer dome 
Definitional Author Sereno 2005 
Definition Status original
textual substitution
first-order revision
second-order revision
Definition Type node
stem
Node-Stem Triplet yes
no
Other Triplet Taxa  
Specifiers
Specifier A Shuvuuia deserti 
Specifier(s) B  
Specifier(s) C Ornithomimus edmontonicus, Tyrannosaurus rex, Therizinosaurus cheloniformis, Oviraptor philocer 
Qualifiers
+Taxon  
-Taxon  
Datum  
Taxonomic Content stem (entirely extinct)
crown (extant-bounded)
mixed (extant/extinct-bounded)
Publication Year 1999 
Inactive Taxon Status Feedback
Rejection Criteria junior synonym
historically polyphyletic
incomplete definition
no definition
apomorphy-based
redundant
other 
Critique  
 
Current Age Range Feedback
Earliest Record Turonian-Coniacian (89 Ma) 
Latest Record Campanian-Maastrichtian (71 Ma) 
Range (My) 18 
Basis for Range The earliest record is Patagonykus puertai from the Turonian-Coniacian (Padian 2004). Mononykus olecranus is the latest record from the Campanian-Maastrichtian. Dates are rounded to the nearest million, the earliest from the beginning of the stage and the latest from the end of the stage (Gradstein et al. 2004). 
Definitional History #1
Definition 1 All ornithomimosaurs closer to Shuvuuia than to Ornithomimus. 
Author Sereno 1999b:2147 
Type node  stem 
Specifiers Shuvuuia, Ornithomimus 
Qualifiers