Dietary Evidence for Competing in the New World Order

Many changes were taking place in the terrestrial landscape near the end of the Mesozoic. Angiosperms are first unequivocally recorded in Cretaceous strata; a rapid diversification and increase in abundance occurred during the Campanian-Maastrichtian. This shift from ferns-gymnosperm to angiosperm dominance was of major importance to terrestrial herbivores. Increasing complexity in the dental batteries of hadrosaurs and ceratopsians also occurred simultaneously. Stable carbon isotopes from teeth have provided detailed information on ecosystem and dietary shifts during the Miocene-Pliocene, with the advent and spread of C4 grasses. However, during the Late Cretaceous all plants probably used only the C3 pathway and carbon isotopes are less useful in distinguishing browsing and grazing habits. However, a large range of carbon isotope values is produced by C3 plants, and indicates that environmental parameters (aridity/humidity) are more important than those produced by taxonomic effects.