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  1. Article: New insights into chasmosaurine (Dinosauria: Ceratopsidae) skulls from the Upper Cretaceous (Campanian) of Alberta, and an update on the distribution of accessory frill fenestrae in Chasmosaurinae.

    Campbell, James A / Ryan, Michael J / Schröder-Adams, Claudia J / Evans, David C / Holmes, Robert B

    PeerJ

    2018  Volume 6, Page(s) e5194

    Abstract: Chasmosaurine ceratopsids are well documented from the Upper Cretaceous (Campanian) Dinosaur Park Formation (DPF) of southern Alberta and Saskatchewan, and ... ...

    Abstract Chasmosaurine ceratopsids are well documented from the Upper Cretaceous (Campanian) Dinosaur Park Formation (DPF) of southern Alberta and Saskatchewan, and include
    Language English
    Publishing date 2018-07-03
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2703241-3
    ISSN 2167-8359
    ISSN 2167-8359
    DOI 10.7717/peerj.5194
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The Braincase and Endosseous Labyrinth of Plioplatecarpus peckensis (Mosasauridae, Plioplatecarpinae), With Functional Implications for Locomotor Behavior.

    Cuthbertson, Robin S / Maddin, Hillary C / Holmes, Robert B / Anderson, Jason S

    Anatomical record (Hoboken, N.J. : 2007)

    2015  Volume 298, Issue 9, Page(s) 1597–1611

    Abstract: Adaptations of mosasaurs to the aquatic realm have been extensively studied from the perspective of modifications to the post-cranial skeleton. In recent years, imaging techniques such as computed tomography have permitted the acquisition of anatomical ... ...

    Abstract Adaptations of mosasaurs to the aquatic realm have been extensively studied from the perspective of modifications to the post-cranial skeleton. In recent years, imaging techniques such as computed tomography have permitted the acquisition of anatomical data from previously inaccessible sources. An exquisitely preserved specimen of the plioplatecarpine mosasaur Plioplatecarpus peckensis presents an opportunity to examine the detailed structure of the braincase, as well as the form of the otic capsule endocast. These data elaborate upon previous descriptions of the braincase of Plioplatecarpus, and provide a detailed, three dimensional reconstruction of the osseous labyrinth for the first time. The otic capsule endocasts reveal that the size of the labyrinth relative to head size is comparable to that of other squamates, suggesting that labyrinth size was not a factor in increasing sensitivity. However, all three semicircular canals are tall and strongly arced to a degree comparable to, and even exceeding, that observed in arboreal and aquatic lizards. Comparison of the sensitivity of the canals in each of the three major axes of rotation suggests Plioplatecarpus peckensis may have been most sensitive to movements in the pitch axis. Although early mosasaurs were probably anguilliform swimmers, most are thought to have been subcarangiform to thunniform locomotors with a near-rigid body form and likely decreased maneuverability. The data from the labyrinth presented here add a potential new dimension to this model of locomotion for further consideration, wherein changes in orientation, such as pitch, may have been more common locomotor behaviors than previously thought.
    MeSH term(s) Adaptation, Physiological ; Anatomic Landmarks ; Animals ; Behavior, Animal ; Biological Evolution ; Cephalometry/methods ; Diving ; Ear, Inner/anatomy & histology ; Ear, Inner/diagnostic imaging ; Ear, Inner/physiology ; Extinction, Biological ; Fossils ; Imaging, Three-Dimensional ; Lizards/anatomy & histology ; Lizards/physiology ; Models, Anatomic ; Motor Activity ; Phylogeny ; Skull/anatomy & histology ; Skull/diagnostic imaging ; Skull/physiology ; Swimming ; X-Ray Microtomography
    Language English
    Publishing date 2015-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2269667-2
    ISSN 1932-8494 ; 1932-8486
    ISSN (online) 1932-8494
    ISSN 1932-8486
    DOI 10.1002/ar.23180
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada.

    Campbell, James A / Ryan, Michael J / Holmes, Robert B / Schröder-Adams, Claudia J

    PloS one

    2016  Volume 11, Issue 1, Page(s) e0145805

    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 ... ...

    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.
    MeSH term(s) Alberta ; Animals ; Dinosaurs/classification ; Fossils ; Phylogeny ; Saskatchewan
    Language English
    Publishing date 2016-01-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1932-6203
    ISSN (online) 1932-6203
    DOI 10.1371/journal.pone.0145805
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Kinetic limitations of intracranial joints in Brachylophosaurus canadensis and Edmontosaurus regalis (Dinosauria: Hadrosauridae), and their implications for the chewing mechanics of hadrosaurids.

    Cuthbertson, Robin S / Tirabasso, Alex / Rybczynski, Natalia / Holmes, Robert B

    Anatomical record (Hoboken, N.J. : 2007)

    2012  Volume 295, Issue 6, Page(s) 968–979

    Abstract: The highly specialized tooth morphology and arrangement of the dental battery of hadrosaurids has led to much speculation surrounding the chewing mechanics of this successful group of herbivorous dinosaurs. Pleurokinesis, a long established hypothesis ... ...

    Abstract The highly specialized tooth morphology and arrangement of the dental battery of hadrosaurids has led to much speculation surrounding the chewing mechanics of this successful group of herbivorous dinosaurs. Pleurokinesis, a long established hypothesis explaining the ornithopod chewing mechanism, proposes a transverse power stroke in hadrosaurids that was accommodated by vertical adduction of the mandible, lateral rotation of the maxilla at the maxilla-premaxilla joint, lateral rotation of the jugal-maxilla complex at its contact with the lacrimal, and posterolateral rotation of the quadrate at its contact with the squamosal. A secondary series of movements were also thought to have occurred as a consequence of these primary movements. In this article, the intracranial joint morphology is described for both Brachylophosaurus canadensis and Edmontosaurus regalis and their permissive kinematics are established. Based on this evidence, the movements associated with pleurokinesis are not accommodated in these hadrosaurine dinosaurs. Rather, the movements that seem most likely to have produced the observed dental wear patterns are those associated with the mandible about the jaw joint. The structure of this joint appears well-suited to have accommodated some translation as well as rotation of the mandible about the quadrate condyle. Three-dimensional modeling of the alternate mandibular movements reveals that not all the combined labiolingual width of the lingual and buccal facets of the tooth row was involved in the power stroke. Rather, limits on the degree of mandibular long axis rotation suggest that only the lingual facet and the more medial portion of the buccal facet were utilized.
    MeSH term(s) Animals ; Cranial Sutures/anatomy & histology ; Cranial Sutures/physiology ; Dentition ; Dinosaurs/anatomy & histology ; Dinosaurs/physiology ; Jaw/anatomy & histology ; Jaw/physiology ; Kinetics ; Mastication/physiology ; Range of Motion, Articular ; Tooth Wear
    Language English
    Publishing date 2012-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2269667-2
    ISSN 1932-8494 ; 1932-8486
    ISSN (online) 1932-8494
    ISSN 1932-8486
    DOI 10.1002/ar.22458
    Database MEDical Literature Analysis and Retrieval System OnLINE

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