Who's Who of the Late Cretaceous
Despite what we read in the papers and see on the silver screen, dinosaurs were not the sole backboned creatures populating the Mesozoic world. By some measures, in fact, they were not even the most important. When dinosaurs are portrayed both in and out of science as the dominant creatures of their day, we are inevitably gauging in human, especially western, frames of reference. We tend to equate dominance with ideas of size, power, and success. Even in the business world, these modifiers can sometimes be difficult to define; when we turn to biology the definitions are even more tenuous.
One way to avoid pitfalls of overgeneralizing about biological dominance or success is to specify how these factors are measured. Some relatively straightforward examples are: sizes of the organisms, the numbers of species in a group, the numbers of individuals in a species or a local population, and how diverse morphologically and thus ecologically a group is. How big, how diverse, how numerous, how morphologically varied were the dinosaurs of the Late Cretaceous, compared with other vertebrates in their biological community? Although I limit my comparison to the latest Cretaceous faunas of eastern Montana, the conclusions drawn from this limited geo-