Home
Archive
RECORDS
Browse
Search
Summarize
Tables
Graphics
Literature Cited
Glossary
View Details:
Prev Record
Next Record
Clade
Subclade
Archosauria: Avemetatarsalia to Neornithes
Taxon
Feedback
Taxon
Marginocephalia
Nominal Author
Sereno 1986
2° Nominal Author
Taxon Status
active
inactive
Comments
Currie and Padian (1997) were first to define Marginocephalia. Independently, Sereno (1998) proposed a very similar definition using genera. Marginocephalia includes two well defined subclades, pachycephalosaurs and ceratopsians. Because there is some uncertainty regarding the monophyly of the clade, negative taxon qualifiers ensure that major external groups will not be included within Marginocephalia. The active definition is a first-order revision of both of these previous definitions.
Potential Synonomy
Active Phylogenetic Definition
Feedback
Active Definition
The least inclusive clade containing
Pachycephalosaurus
wyomingensis
(Gilmore 1931) and
Triceratops
horridus
Marsh 1889 but excluding
Heterodontosaurus
tucki
Crompton and Charig 1962,
Hypsilophodon
foxii
Huxley 1869,
Ankylosaurus
magniventris
Brown 1908.
Shorthand
<
Pachycephalosaurus
wyomingensis
and
Triceratops
horridus
—
Heterodontosaurus
tucki
,
Hypsilophodon
foxii
,
Ankylosaurus
magniventris
.
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
Pachycephalosauria, Ceratopsia
Specifiers
Specifier A
Pachycephalosaurus
wyomingensis
Specifier(s) B
Triceratops
horridus
Specifier(s) C
Qualifiers
+Taxon
-Taxon
Heterodontosaurus
tucki
,
Hypsilophodon
foxii
,
Ankylosaurus
magniventris
Datum
Taxonomic Content
stem (entirely extinct)
crown (extant-bounded)
mixed (extant/extinct-bounded)
Publication Year
1997
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
Berriasian (146 Ma)
Latest Record
Maastrichtian (66 Ma)
Range (My)
80
Basis for Range
The earliest record is Berriasian-age
Stenopelix
valdensis
from the Obernkirchen Sandstone of Germany. The latest record is Maastrichtian-age pachycephalosaurs and ceratopsians from Asia and western North America (Weishampel et al. 2004). Dates are rounded to the nearest million, the earliest from the beginning of the stage and the latest from the end of the stage (Gradstein et al. 2004).
Definitional History #1
Definition 1
Ceratopsia and Pachycephalosauria and all descendants of their most recent common ancestor.
Author
Currie and Padian 1997:415
Type
node
stem
Specifiers
Ceratopsia, Pachycephalosauria
Qualifiers
Definitional History #2
Definition 2
Pachycephalosaurus
,
Triceratops
, their most recent common ancestor and all descendants.
Author
Sereno 1998:62
Type
node
stem
Specifiers
Pachycephalosaurus
,
Triceratops
Qualifiers
