View Details:  Prev Record    Next Record
Clade
Subclade

Taxon
Taxon
Ornithopoda
Nominal Author
Marsh 1881
2nd Nominal Author
Taxon Status ACTIVE
Comments

Sereno (1998) initially proposed a node-based definition for Ornithopoda and constructed a node-stem triplet with its two subclades, stem-based Heterodontosauridae and Euornithopoda. Without referencing this initial definition or providing further explanation, Norman et al. (2004) proposed a stem-based definition for Ornithopoda.

The active definition is a first-order revision of Sereno (1998) that also includes several negative taxon qualifiers, so that the taxon Ornithopoda will not apply to a much larger clade within Ornithischia, should heterodontosaurids prove more closely related to any other clade besides Euornithopoda. If the analysis of Sereno (1999) is confirmed by later studies, the taxon is available and would correspond fairly closely to the content with which it has been associated since the mid 1980’s.

Recently Butler (2005) has suggested that most ornithopods (i.e. what may be regarded as euornithopods) share a closer relationship with Marginocephalia than with heterodontosauirds. If this is confirmed by later studies, then the taxon Ornithopoda as here defined would not be applicable.

Potential Synonomy

Active Phylogenetic Definition
Active Definition
The least inclusive clade containing Heterodontosaurus tucki Crompton and Charig 1962 and Parasaurolophus walkeri Parks 1922 but excluding Pachycephalosaurus wyomingensis (Gilmore 1931), Triceratops horridus Marsh 1889, Ankylosaurus magniventris Brown 1908.
Shorthand
< Heterodontosaurus tucki and Parasaurolophus walkeriPachycephalosaurus wyomingensis, Triceratops horridus, Ankylosaurus magniventris.
Definitional Author
Sereno 2005
Definition Status checked
Definition Type NODE
Node-Stem Triplet NODE
Other Triplet Taxa
Heterdontosauridae, Euornithopoda
Specifiers
Specifier(s) A
Heterodontosaurus tucki
Specifier(s) B
Parasaurolophus walkeri
Specifier(s) C
Qualifiers
+Taxon
-Taxon
Pachycephalosaurus wyomingensis, Triceratops horridus, Ankylosaurus magniventris
Datum
Taxonomic Content
Publication Year Unknown
Unknown
Unknown
1998

Inactive Taxon Status
Rejection Criteria
Critique
 

Definitional History #1
Earliest Record
Heterodontosaurus, Parasaurolophus, their most recent common ancestor and all descendants.
Latest Record
Sereno 1998:61
Range (My)
Range (My)
Heterodontosaurus, Parasaurolophus
Range (My)

Definitional History #2
Earliest Record
All cerapodans closer to Edmontosaurus than to Triceratops.
Latest Record
Norman et al. 2004:393
Range (My)
Range (My)
Edmontosaurus, Triceratops
Range (My)

Definitional History #3
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #4
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #5
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #6
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #7
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #8
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #9
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #10
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)