Book contents
- Frontmatter
- Contents
- Why a natural history of dinosaurs?
- Dedication
- Part I Reaching back in time
- Part II Ornithischia: armored, horned, and duck-billed dinosaurs
- 5 Thyreophorans: the armor-bearers
- 6 Marginocephalia: bumps, bosses, and beaks
- 7 Ornithopoda: the tuskers, antelopes, and “mighty ducks” of the Mesozoic
- Part III Saurischia: meat, might, and magnitude
- Part IV Endothermy, endemism, and extinction
- Glossary
- Figure credits
- Index of subjects
- Index of genera
6 - Marginocephalia: bumps, bosses, and beaks
- Frontmatter
- Contents
- Why a natural history of dinosaurs?
- Dedication
- Part I Reaching back in time
- Part II Ornithischia: armored, horned, and duck-billed dinosaurs
- 5 Thyreophorans: the armor-bearers
- 6 Marginocephalia: bumps, bosses, and beaks
- 7 Ornithopoda: the tuskers, antelopes, and “mighty ducks” of the Mesozoic
- Part III Saurischia: meat, might, and magnitude
- Part IV Endothermy, endemism, and extinction
- Glossary
- Figure credits
- Index of subjects
- Index of genera
Summary
Chapter objectives
Introduce Marginocephalia, particularly its two large constituent groups, Pachycephalosauria and Ceratopsia
Develop familiarity with current thinking about lifestyles and behaviors of marginocephalians
Develop an understanding of marginocephalian evolution using cladograms, and an understanding of the place of Marginocephalia within Dinosauria
Marginocephalia
Who were marginocephalians?
Marginocephalia (margin – edge; kephale – head). It's not a name you'll hear from the local 5-year-old dino-it-all. Yet, the name Marginocephalia reflects an important connection between two major, superficially different-looking, groups of dinosaurs: Pachycephalosauria (pachy – thick;) and Ceratopsia (kera – horn; ops – face). Together with Ornithopoda (Chapter 7), marginocephalians make up the taxon known as Cerapoda (Figure 6.1).
Marginocephalians all bear a ridge, or shelf, of bone running across the back of the skull. The size of this feature varies greatly, but in all cases, when viewed from above, it blocks from sight the bones at the back of the skull.
Although marginocephalians come in many shapes and sizes, they were restricted to the Northern Hemisphere during the Cretaceous Period.
Marginocephalia: Pachycephalosauria – In Domes We Trust
Pachycephalosaurs were bipedal ornithischians with thickened skull roofs (Figure 6.2). In the North American pachycephalosaurs, this took the form of high domes, but several Asian varieties had flattened, thickened skulls (Figure 6.3); some, however, are considered to be juvenile forms of fully adult dome-headed pachycephalosaurs. Figure 6.4 shows the distinctive Northern Hemisphere distribution of pachycephalosaur sites.
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- Information
- DinosaursA Concise Natural History, pp. 108 - 133Publisher: Cambridge University PressPrint publication year: 2009