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Re: Kosmoceratops not present in Dinosaur Park Formation of Canada



Interesting paper on Chasmosaurus systematics. 

Btw, does anyone know if PLoS ONE normally releases updated 
PDFs, or is this the final version of the paper..?  I ask because 
none of the single-column figures are formatted [yet] as 
single column--they're all just tossed in as full page width, 
which makes for lengthier printing (you can tell that some 
were intended as single column because "planned for column 
width" hasn't been removed from the end of the caption). 

Formatting those single column figs. can complicate page 
layout, but I think it's worth it even in a paper you'll only 
be viewing on-screen.

    Paul P.

(and apologies for yahoo's mangling of the original post 
below)

--------------------------------------------
On Mon, 1/4/16, Ben Creisler <bcreisler@gmail.com> wrote:

 Subject: Kosmoceratops not present in Dinosaur Park Formation of Canada
 To: dinosaur@usc.edu
 Date: Monday, January 4, 2016, 1:07 PM
 
 Ben Creisler bcreisler@gmail.com
 
 New in PLoS ONE:
 
 James A. Campbell, Michael J. Ryan, Robert B. Holmes & Claudia J.
 Schröder-Adams (2016)
 A Re-Evaluation of the Chasmosaurine Ceratopsid Genus
 Chasmosaurus
 (Dinosauria: Ornithischia) from the Upper Cretaceous
 (Campanian)
 Dinosaur Park Formation of Western Canada.
 PLoS ONE 11(1): e0145805.
 doi:10.1371/journal.pone.0145805
 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0145805
 
 Background
 
 The chasmosaurine ceratopsid Chasmosaurus is known from the
 Upper
 Cretaceous (Campanian) Dinosaur Park Formation of southern
 Alberta and
 Saskatchewan. Two valid species, Chasmosaurus belli and C.
 russelli,
 have been diagnosed by differences in cranial ornamentation.
 Their
 validity has been supported, in part, by the reported
 stratigraphic
 segregation of chasmosaurines in the Dinosaur Park
 Formation, with C.
 belli and C. russelli occurring in discrete, successive
 zones within
 the formation.
 
 Results/Conclusions
 
 An analysis of every potentially taxonomically informative
 chasmosaurine specimen from the Dinosaur Park Formation
 indicates that
 C. belli and C. russelli have indistinguishable ontogenetic
 histories
 and overlapping stratigraphic intervals. Neither taxon
 exhibits
 autapomorphies, nor a unique set of apomorphies, but they
 can be
 separated and diagnosed by a single phylogenetically
 informative
 character—the embayment angle formed by the posterior
 parietal bars
 relative to the parietal midline. Although relatively deeply
 embayed
 specimens (C. russelli) generally have relatively longer
 postorbital
 horncores than specimens with more shallow embayments (C.
 belli),
 neither this horncore character nor epiparietal morphology
 can be used
 to consistently distinguish every specimen of C. belli from
 C.
 russelli.
 
 Status of Kosmoceratops in the Dinosaur Park Formation
 
 Kosmoceratops is purportedly represented in the Dinosaur
 Park
 Formation by a specimen previously referred to Chasmosaurus.
 The
 reassignment of this specimen to Kosmoceratops is
 unsupported here, as
 it is based on features that are either influenced by
 taphonomy or
 within the realm of individual variation for Chasmosaurus.
 Therefore,
 we conclude that Kosmoceratops is not present in the
 Dinosaur Park
 Formation, but is instead restricted to southern Laramidia,
 as
 originally posited.