Anatomy, systematics, and evolution of Oviraptorosauria (Dinosauria, Theropoda)

• Author / Creator

  Funston, Gregory F

• Here I describe new oviraptorosaur specimens and add to our knowledge of the anatomy, growth, behaviour, ecology, and evolution of oviraptorosaurs. Oviraptorosaurs were a diverse group of theropods known from a long history of discovery and a relatively abundant fossil record. Most analyses divide the toothless members of the clade into three families: Avimimidae, Caenagnathidae, and Oviraptoridae. New avimimid specimens, including bonebed assemblages, show the unusual cranial anatomy of avimimids, compared to other oviraptorosaurs, and add to their diversity. The composition of these bonebeds as revealed by osteohistology indicates that avimimids formed flocks with mixed age representation. Additional caenagnathid material from the Dinosaur Park and Nemegt Formations of Alberta and Mongolia, respectively, improves skeletal representation for these poorly known animals. Osteohistology reveals the growth dynamics of Dinosaur Park Formation caenagnathids and shows that they can be divided into three taxa of varying body sizes and morphologies. A new, well-represented taxon—Apatoraptor pennatus—from the Horseshoe Canyon Formation is described and provides information on the skeletal proportions and taxonomy of caenagnathids. Histological analysis of the fused dentaries shows the patterns of mandibular development and confirms the absence of teeth at any point in development. Mongolian oviraptorids are reviewed, including historic specimens and newly discovered material that improves our knowledge of their anatomy. A new, exceptionally preserved oviraptorid is represented by nearly every element and multiple individuals forming an ontogenetic growth series. This unusual, gregarious taxon has a domed cranial crest and only two functional manual digits. Using the new specimens, the gregarious behaviour, ecology, and evolution of oviraptorosaurs is reviewed. New oviraptorosaur assemblages improve our understanding of their gregarious behaviour, which was more ubiquitous than previously recognized and probably persisted throughout ontogeny. Community ecology data show that oviraptorosaurs were a small but stable part of Late Cretaceous ecosystems of the Western Gobi Desert of Mongolia. Incorporation of the new specimens into a phylogenetic analysis provides unprecedented clarity of oviraptorosaur relationships, allowing biogeography, body mass evolution, digit reduction and gregarious behaviour to be analysed in detail. Range expansion played a major role in oviraptorosaur evolution, leading to major taxonomic and morphological radiations in North America and the Western Gobi Desert.

• Subjects / Keywords

  • Evolution
  • Dinosaur
  • Palaeontology

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-2w53-m477

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.