Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta
The Dinosaur Park Formation (DPF) has a diverse assemblage of chasmosaurines currently represented by Chasmosaurus belli, C. russelli, Vagaceratops irvinensis, and Mercuriceratops gemini, and may also include remains possibly referable to Spiclypeus shipporum. Two skulls, YPM 2016 and AMNH 5402, pre...
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| Format: | Article |
| Language: | English |
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University of Alberta Libraries
2019-08-01
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| Series: | Vertebrate Anatomy, Morphology, Palaeontology |
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| Online Access: | https://journals.library.ualberta.ca/vamp/index.php/VAMP/article/view/29356 |
| _version_ | 1818110546105335808 |
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| author | James Alexander Campbell Michael J. Ryan Claudia J. Schroder-Adams Robert B. Holmes David C. Evans |
| author_facet | James Alexander Campbell Michael J. Ryan Claudia J. Schroder-Adams Robert B. Holmes David C. Evans |
| author_sort | James Alexander Campbell |
| collection | DOAJ |
| description | The Dinosaur Park Formation (DPF) has a diverse assemblage of chasmosaurines currently represented by Chasmosaurus belli, C. russelli, Vagaceratops irvinensis, and Mercuriceratops gemini, and may also include remains possibly referable to Spiclypeus shipporum. Two skulls, YPM 2016 and AMNH 5402, previously referred to C. belli, both have a straight posterior parietal bar with five epiparietals present (YPM 2016) or inferred (AMNH 5402) on each side – the combination of which is unique to V. irvinensis. Based on our new morphological observations and interpretations of these two skulls, we recover V. irvinensis as a species of Chasmosaurus (C. irvinensis), although the interrelationships between C. irvinensis, C. belli, and C. russelli remain unclear. We refrain from formerly assigning YPM 2016 and AMNH 5402 to C. irvinensis, however, as their parietal fenestrae are significantly larger and their epiparietals are significantly shorter than those of C. irvinensis; instead, we reassign these two skulls to Chasmosaurus sp. Given the low stratigraphic position of YPM 2016 (unknown in AMNH 5402) relative to C. irvinensis, we believe this specimen to represent a basal member of the lineage leading to C. irvinensis. If our assessment is correct, this would indicate that the C. irvinensis lineage has a large degree of stratigraphic overlap with that of C. belli and C. russelli. The close phylogenetic relationship and supposed stratigraphic separation for these three taxa reported in previous studies were used to suggest that they may represent an anagenetic lineage, whereby C. russelli evolved into C. belli, and C. belli evolved into, and was entirely replaced by, the latter. However, the lack of stratigraphic separation between these three taxa indicates that they instead arose via cladogenesis. |
| first_indexed | 2024-12-11T02:48:52Z |
| format | Article |
| id | doaj.art-8547e83bb7344290b16082e7432834fb |
| institution | Directory Open Access Journal |
| issn | 2292-1389 |
| language | English |
| last_indexed | 2024-12-11T02:48:52Z |
| publishDate | 2019-08-01 |
| publisher | University of Alberta Libraries |
| record_format | Article |
| series | Vertebrate Anatomy, Morphology, Palaeontology |
| spelling | doaj.art-8547e83bb7344290b16082e7432834fb2022-12-22T01:23:21ZengUniversity of Alberta LibrariesVertebrate Anatomy, Morphology, Palaeontology2292-13892019-08-01710.18435/vamp29356Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of AlbertaJames Alexander CampbellMichael J. RyanClaudia J. Schroder-AdamsRobert B. HolmesDavid C. EvansThe Dinosaur Park Formation (DPF) has a diverse assemblage of chasmosaurines currently represented by Chasmosaurus belli, C. russelli, Vagaceratops irvinensis, and Mercuriceratops gemini, and may also include remains possibly referable to Spiclypeus shipporum. Two skulls, YPM 2016 and AMNH 5402, previously referred to C. belli, both have a straight posterior parietal bar with five epiparietals present (YPM 2016) or inferred (AMNH 5402) on each side – the combination of which is unique to V. irvinensis. Based on our new morphological observations and interpretations of these two skulls, we recover V. irvinensis as a species of Chasmosaurus (C. irvinensis), although the interrelationships between C. irvinensis, C. belli, and C. russelli remain unclear. We refrain from formerly assigning YPM 2016 and AMNH 5402 to C. irvinensis, however, as their parietal fenestrae are significantly larger and their epiparietals are significantly shorter than those of C. irvinensis; instead, we reassign these two skulls to Chasmosaurus sp. Given the low stratigraphic position of YPM 2016 (unknown in AMNH 5402) relative to C. irvinensis, we believe this specimen to represent a basal member of the lineage leading to C. irvinensis. If our assessment is correct, this would indicate that the C. irvinensis lineage has a large degree of stratigraphic overlap with that of C. belli and C. russelli. The close phylogenetic relationship and supposed stratigraphic separation for these three taxa reported in previous studies were used to suggest that they may represent an anagenetic lineage, whereby C. russelli evolved into C. belli, and C. belli evolved into, and was entirely replaced by, the latter. However, the lack of stratigraphic separation between these three taxa indicates that they instead arose via cladogenesis.https://journals.library.ualberta.ca/vamp/index.php/VAMP/article/view/29356CampanianChasmosaurusDinosaur Park FormationevolutionLaramidiastratigraphy |
| spellingShingle | James Alexander Campbell Michael J. Ryan Claudia J. Schroder-Adams Robert B. Holmes David C. Evans Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta Vertebrate Anatomy, Morphology, Palaeontology Campanian Chasmosaurus Dinosaur Park Formation evolution Laramidia stratigraphy |
| title | Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta |
| title_full | Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta |
| title_fullStr | Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta |
| title_full_unstemmed | Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta |
| title_short | Temporal range extension and evolution of the chasmosaurine ceratopsid ‘Vagaceratops’ irvinensis (Dinosauria: Ornithischia) in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta |
| title_sort | temporal range extension and evolution of the chasmosaurine ceratopsid vagaceratops irvinensis dinosauria ornithischia in the upper cretaceous campanian dinosaur park formation of alberta |
| topic | Campanian Chasmosaurus Dinosaur Park Formation evolution Laramidia stratigraphy |
| url | https://journals.library.ualberta.ca/vamp/index.php/VAMP/article/view/29356 |
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