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Clade
Subclade Archosauria: Crurotarsi to Crocodylia 

Taxon Feedback
Taxon Sphagesauridae 
Nominal Author Kuhn 1968 
2° Nominal Author  
Taxon Status active
inactive
Comments

This taxon, as coined by Kuhn (1968) and used by Steel (1973), was a monotypic family redundant with the Late Cretaceous Sphagesaurus hueni. The type of Sphagesaurus huenei consists only of two teeth, but these are very derived in form with fluted crowns (Price 1950). Recent discovery of a partial cranium of the species (Pol 2003) shows that S. hueni is a derived notosuchian crocodyliform closely related to the Chinese species Chimerosuchus paradoxus (Wu and Sues 1996). The evidence is strong and consists of the presence of only two premaxillary teeth, the participation of the premaxilla in the dorsal margin of the external naris, and other features (Pol 2003).

Independently, Chimaerasuchidae was coined by Carvalho et al. (2004) and defined with a node-based definition to include Chimaerasuchus and Simosuchus. This group, in contrast, has not been supported by other analyses and is united on the basis of weak, homoplastic character evidence (Carvalho et al. 2004:988). The family Sphagesauridae Kuhn 1968 has precedence over Chimaerasuchidae Carvalho et al. 2004, and the existence of this derived clade is now very strong.

Nevertheless, these two taxa are not synonyms by definition; Chimaerasuchidae, defined using Simosuchus as an internal specifier (Carvalho et al. 2004), will circumscribe some as yet uncertain, larger clade (depending on the position of Simosuchus). The active definition Sphagesauridae is stem-based and cites as external specifiers the best known, nominotypic species of other notosuchians and extant Crocodylia, ensuring the inclusion only of forms most closely related to Sphagesaurus huenei.

 
Potential Synonomy Chimaerasuchidae 

Active Phylogenetic Definition Feedback
Active Definition The most inclusive clade containing Sphagesaurus huenei Price 1950 but not Baurusuchus pachecoi Price 1945, Sebecus icaeorhinus Simpson 1937, Araripesuchus gomesii Price 1959, Comahuesuchus brachybuccalis Bonaparte 1991, Simosuchus clarki Buckley et al. 2000, Notosuchus terrestris Woodward 1896, Crocodylus niloticus (Laurenti 1768). 
Shorthand > Sphagesaurus hueni but not Baurusuchus pachecoi, Sebecus icaeorhinus, Araripesuchus gomesii, Comahuesuchus brachybuccalis, Simosuchus clarki
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 Sphagesaurus hueni 
Specifier(s) B  
Specifier(s) C Baurusuchus pachecoi, Sebecus icaeorhinus, Araripesuchus gomesii, Comahuesuchus brachybuccalis, Simosuchus clarki, Notosuchus terrestris, Crocodylus niloticus 
Qualifiers
+Taxon  
-Taxon  
Datum  
Taxonomic Content stem (entirely extinct)
crown (extant-bounded)
mixed (extant/extinct-bounded)
Publication Year 2005 

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 Aptian-Albian (112 Ma) 
Latest Record Turonian-Santonian (89 Ma) 
Range (My) 23 
Basis for Range The earliest record is Chimaerasuchus paradoxus from the Aptian-Albian-age Wulong Formation of Hubei Province, central China (Wu and Sues 1996). The latest record is Sphagesaurus hueni (Pol 2003) from the Turonian-Santonian-age Adamantina Formation in southern Brazil (Carvalho et al. 2005). Dates are rounded to the nearest million, the earliest and the latest from the boundary and midpoint, respectively, between the successive stages listed as first and last occurrences (Gradstein et al. 2004).