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Ceratops analyzed in the Sampson et al. (2010) matrix
With all of this discussion of Ceratops lately, isn't it about time someone do
some science to solve the question of what it is? The newly published paper by
Sampson et al. (2010) describing Utahceratops and Kosmoceratops includes the
largest ceratopsid analysis to date. It also includes both long-horned basal
ceratopsomorphs Zuniceratops and Turanoceratops and the long-horned basal
centrosaurine Albertaceratops. Ceratops could be coded for 7 of the 148
characters. It emerges as the sister taxon of Utahceratops within
'chasmosaurine' ceratopsids. Thus there is no difficulty defining Ceratopsidae
or Ceratopsinae based on Ceratops.
Relevent characters include-
- Supraorbital horn sinus enters postorbital, which is only present in
ceratopsids.
- Supraorbital horn core centered posterodorsal to orbit, broad base with
posterior margin of supraorbital horncore extending well behind posterior
orbit, which is only present in Pachyrhinosaurus, Utahceratops and the
Anchiceratops+Triceratops clade.
- Supraorbital horn core dorsolaterally directed, which is shared with
'chasmosaurines' more derived than Chasmosaurus, but reversed in Triceratops
sensu lato.
- Supraorbital horn core straight in lateral view, which is shared with
Centrosaurus and Utahceratops.
Note it also has a unique combination of characters, so it not a nomen dubium.
It differs least from Utahceratops (except for the long brow horns) and
Anchiceratops and Arrhinoceratops (except for the straight, not recurved, brow
horns).
The codings for Ceratops are-
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Mickey Mortimer