The evidence based upon times of occurrence in the fossil record (Prieto-Márquez, 2010:fig. 10) suggests that the pattern of diversification of euhadrosaurians displays a significant lag phase during the Coniacian–Santonian before a log-phase diversification in the Campanian and an equilibration during the Maastrichtian. Whether this pattern is an artifact of preservation in the fossil record, or represents some element of “bottle-necking” associated with the process of assembly of euhadrosaurian anatomy (and implicit biology), cannot yet be resolved satisfactorily.
ACKNOWLEDGMENTS AND DEDICATION
I would like to thank a very old friend, Dave Eberth, for inviting me to attend this symposium. Circumstances dictated that his co-organizer and co-editor, David Evans, had the unenviable task of presenting my talk because a family bereavement prevented me from attending the meeting. I am also indebted to David Weishampel for savagely criticizing another draft manuscript that is of relevance to this contribution (and hence thank him for indirectly contributing to this article). David Evans and Paul Barrett, my formal reviewers, were unstinting in their critical commentaries and made a number of valuable observations and cogent points that helped to turn a far too rapidly produced first draft into a better-structured, and more cogent, revised version. None of the above can take any blame for the remaining errors; the latter will, perforce, fall upon my shoulders.
This chapter is, of course, dedicated to a dear friend whom I first met when he visited me in London and Oxford University in the early 1980s (our having corresponded for some time before over matters relating to ornithopod jaw mechanisms and their implications). Suffice it to say we saw eye to eye rather than tooth to claw pretty much immediately and became firm friends (we are, after all, both named David Bruce and were born in the same year); and, despite a few ups and downs along the way, we have never lost that core friendship. So it is with pleasure (and a little amusement) that I contribute to a volume on hadrosaurs in Dave’s honor when I know so little about such exotic beasts, especially given that old canard that Dave W. has undoubtedly forgotten more about hadrosaurs than Dave N. will ever know.
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