Pachycephalosaur diversity and systematics is poorly resolved, mainly due to the incomplete nature of their remains. The largest sample of pachycephalosaurs is from the Belly River Group of Alberta, but this sample is also the most problematic in terms of alpha taxonomic diversity. Material from this assemblage has been proposed to represent from a single species to up to four distinct genera. Each of these views depends on different interpretations of morphology, ornamentation, ontogeny, and sexual dimorphism, but none have been adequately tested. Here I analyze the diversity of pachycephalosaurs with particular emphasis on Stegoceras validum and 'Prenocephale' brevis. The ontogeny of these species is described using comparative morphology, histology, and morphometrics. New specimens are described and the first detailed pachycephalosaur growth series supported by multiple, independent lines of evidence is presented. Phylogenetic analysis utilizing results from this study provides a new hypothesis for the evolutionary relationships of pachycephalosaurs.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/27360 |
| Date | 31 May 2011 |
| Creators | Schott, Ryan K. |
| Contributors | Evans, David C. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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