Literature Cited

View Details:  Prev Record   Next Record

Subclade Archosauria: Crurotarsi to Crocodylia 

Taxon Feedback
Taxon Crocodylomorpha 
Nominal Author Hay 1930 
2° Nominal Author  
Taxon Status active

Walker (1968) was first to use the taxon Crocodylomorpha, which is here considered a spelling variant of Hay’s (1930) taxon Crocodylomorphi. Many references in the literature cite Wlaker (1970) as the origin of this taxon name. The name was first used explcitly as a clade by Clark (in Benton and Clark 1988; sensu Walker 1968). Despite its widespread use, the taxon seems never to have been defined.

The active definition is stem-based so that Crocodylomorpha includes all taxa closer to extant crocodilians than to any other recognized suchian subclade. A number of external specifiers are included to ensure stability of taxonomic content in the face of shifting relationships immediately outside the clade. A potential synonmym is Crocodylia in its traditional sense (e.g. Steel 1973), although Crocodylia has never been given a phylogenetic definition with this content.

Potential Synonomy Crocodylomorphi (Hay 1930, precursor), Crocodylia 

Active Phylogenetic Definition Feedback
Active Definition The most inclusive clade containng Crocodylus niloticus (Laurenti 1768) but not Poposarus gracilis Mehl 1915, Gracilisuchus stipanicicorum Romer 1972, Prestosuchus chiniquensis Huene 1942, Aetosaurus ferratus Fraas 1877. 
Shorthand > Crocodylus niloticus but not Poposarus gracilis, Gracilisuchus stipanicicorum, Prestosuchus chiniquensis, Aetosaurus ferratus
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 Paracrocdylomorpha, Poposauridae 
Specifier A Crocodylus niloticus 
Specifier(s) B  
Specifier(s) C Poposarus gracilis, Gracilisuchus stipanicicorum, Prestosuchus chiniquensis, Aetosaurus ferratus 
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

Current Age Range Feedback
Earliest Record Carnian (228 Ma) 
Latest Record Recent 
Range (My) 228 
Basis for Range The earliest record are sphenosuchians such as Hesperosuchus agilis from the late Carnian-age lower portion of the Petrified Forest Member of the Chinle Formation of Arizona (Clark et al. 2000). The latest records are extant crocodilians. Dates are rounded to the nearest million, the earliest from the beginning of the stage (Gradstein et al. 2004). 

Additional Definitional History: None Available