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A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada.
PLoS One. 2016; 11(1):e0145805.Plos

Abstract

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.

Links

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Authors+Show Affiliations

Campbell JA
Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada. Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
Ryan MJ
Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada. Department of Vertebrate Paleontology, Cleveland Museum of Natural History, Cleveland, Ohio, United States of America.
Holmes RB
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Schröder-Adams CJ
Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada.

MeSH

AlbertaAnimalsDinosaursFossilsPhylogenySaskatchewan

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26726769

Citation

Campbell, James A., et al. "A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) From the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada." PloS One, vol. 11, no. 1, 2016, pp. e0145805.
Campbell JA, Ryan MJ, Holmes RB, et al. A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada. PLoS One. 2016;11(1):e0145805.
Campbell, J. A., Ryan, M. J., Holmes, R. B., & Schröder-Adams, C. J. (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. https://doi.org/10.1371/journal.pone.0145805
Campbell JA, et al. A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) From the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada. PLoS One. 2016;11(1):e0145805. PubMed PMID: 26726769.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada. AU - Campbell,James A, AU - Ryan,Michael J, AU - Holmes,Robert B, AU - Schröder-Adams,Claudia J, Y1 - 2016/01/04/ PY - 2015/07/28/received PY - 2015/12/07/accepted PY - 2016/1/5/entrez PY - 2016/1/5/pubmed PY - 2016/7/9/medline SP - e0145805 EP - e0145805 JF - PloS one JO - PLoS One VL - 11 IS - 1 N2 - 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. SN - 1932-6203 UR - https://www.unboundmedicine.com/medline/citation/26726769/A_Re_Evaluation_of_the_Chasmosaurine_Ceratopsid_Genus_Chasmosaurus__Dinosauria:_Ornithischia__from_the_Upper_Cretaceous__Campanian__Dinosaur_Park_Formation_of_Western_Canada_ DB - PRIME DP - Unbound Medicine ER -