CRETACEOUS DISTRIBUTION PATTERNS OF HERBIVOROUS DINOSAURS AND VASCULAR PLANTS: USING MAP SEQUENCES TO EXAMINE CO-EVOLUTIONARY PATTERNS

We have investigated whether the end-Cretaceous radiation of the angiosperms was correlated with the contemporaneous success of some groups of ornithischian dinosaurs (hadrosaurians, ceratopsians). The hypothesized association between these plants and dinosaurs was tested by examining the potential similarity in geographic and temporal distribution of plant and dinosaur fossils throughout North America. Data on age of formation, relative taxonomic diversity, and location of fossil plants and dinosaurs were compiled from existing literature. Analysis of the distribution of these two fossil groups through time provides a basis for testing the hypothesized interaction between herbivorous dinosaurs and plants. While North America currently offers the best Cretaceous terrestrial fossil record, data points are still sparse. Based on trends in available data, there is indication that hadrosaurians co-occur with floras having a relatively high percentage of angiosperm taxa. Ceratopsians initially tend to occur in areas dominated by pteridophytes and only by the end of the Cretaceous do they co-occur with angiosperm-dominated floras.