December 9 2009
12:00 LSB 2320
Raymond M. Alf Museum of Paleontology
The Horned Dinosaurs: Anatomy of an Evolutionary Radiation
Summary:
The ceratopsids, or horned dinosaurs, were characterized by a bewildering array of cranial ornamentation. Recent discoveries, particularly in the southern extent of the Western Interior Basin of North America, have revealed a hitherto unknown diversity for this clade. This explosion of diversity--at least 35 species of ceratopsid are now known--occured over a period of less than 15 million years. Although basal ceratopsids show some variation in the "snout" region, species differentiation within the two major ceratopsid subfamilies (Centrosaurinae and Chasmosaurinae) is accomplished almost exclusively through the highly variable morphology of the nasal horns, brown horns and bony neck frill. Even the postcrania are extremely conservative across species. Thus, extensive speculation has focused on the function of the cranial structures: were they for display, combat, defense, or some combination of these functions? In this seminar, I will discuss some new approaches and insights on the evolution and functional morphology of ceratopsids.