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 walkeri —Pachycephalosaurus 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) |
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Definitional History #7 | |
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Definitional History #8 | |
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Definitional History #9 | |
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Definitional History #10 | |
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