Clade | |
Subclade |
Taxon | |
Taxon |
Thyreophora
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Nominal Author | Nopcsa 1915 |
2nd Nominal Author | |
Taxon Status | ACTIVE |
Comments | Thyreophora was first defined by Sereno (1998) as a stem-based taxon, using Ankylosaurus and Triceratops as internal and external specifiers, respectively. Although Nopcsa (1915) originally included ceratopsids (and thus all obligate quadrupedal ornithischians), the taxon has been limited to armored ornithischians ever since the initial cladistic analyses of Ornithischia (Sereno 1986) and was defined in this manner by (Sereno 1998) and by three authors in The Dinosauria (Weishampel et al. 2004). The active definition is a first-order revision of the original definitionin that uses species as specifiers. It also introduces two external specifiers to stabilize taxonomic content. The additional external specifiers exclude members of other ornithischian clades that otherwise might be included under alternative phylogenetic arrangements. Note that Cooper (1985:287) appeared to coin a new taxon "Thyreohporina," but he attributed this taxon to Nopcsa (1915). As he did not use Thyreophora elsewhere in his classification, his new taxon is interpreted here as a spelling error meant to refer to Thyreophora. Thyreophorina, in any case, is already in use within Diptera. |
Potential Synonomy | Thyreophorina (Cooper 1985, misspelling; preoccupied by a taxon within Diptera) |
Active Phylogenetic Definition | |
Active Definition |
The most inclusive clade containing Ankylosaurus magniventris Brown 1908 but not Parasaurolophus walkeri Parks 1922, Pachycephalosaurus wyomingensis (Gilmore 1931), Triceratops horridus Marsh 1889.
|
Shorthand |
> Ankylosaurus magniventris but not Parasaurolophus walkeri, Pachycephalosaurus wyomingensis, Triceratops horridus. |
Definitional Author |
Sereno 2005 |
Definition Status | checked |
Definition Type | STEM |
Node-Stem Triplet | STEM |
Other Triplet Taxa |
Genasauria, Neornithischia |
Specifiers | |
Specifier(s) A |
Ankylosaurus magniventris |
Specifier(s) B | |
Specifier(s) C |
Parasaurolophus walkeri, Pachycephalosaurus wyomingensis, Triceratops horridus
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Qualifiers | |
+Taxon | |
-Taxon | |
Datum | |
Taxonomic Content | |
Publication Year |
Unknown Unknown Unknown 1998 |
Inactive Taxon Status | |
Rejection Criteria | |
Critique | |
Definitional History #1 | |
Earliest Record | All genasaurs closer to Ankylosaurus than to Triceratops. |
Latest Record | Sereno 1998:61 |
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Ankylosaurus, Triceratops |
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