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HADROSAURS – ALSO KNOWN AS DUCK-BILLED DINOSAURS – are one of the best-known groups within Dinosauria due to their abundance in the fossil record, notable diversity, and near global distribution in the Late Cretaceous. Their success was likely driven by a combination of factors that included, most importantly, anatomically-unique and functionally-complex jaws and dentitions that processed plants more efficiently than those of any “reptile” before or since. Ultimately, the ubiquity of hadrosaurs in the Cretaceous fossil record has allowed us to learn more about dinosaurian paleobiology and paleoecology than we have from any other group.

In recent years, a number of dinosaur groups have been the subject of renewed scientific interest. In 2005, sauropod studies experienced a scientific renaissance with the benchmark publications The Sauropods: Evolution and Paleobiology and Indiana University Press’s Thunder Lizards: The Sauropodomorph Dinosaurs. In 2010, after a decade-long surge of interest in horned dinosaurs, that group received similar treatment in Indiana University Press’s New Perspectives on Horned Dinosaurs. During the last five years it has been the hadrosaurs’ time in the spotlight. Due to the rapidly growing fossil record as well as widespread international collaborations, researchers from around the world are now studying new specimens and taxa of hadrosaurs to clarify their origins, patterns of evolution, function, paleobiology, paleobiogeography, and preservation.

It was with this perspective that we (Davids 1 and 2) convened the International Hadrosaur Symposium (September 22–23, 2011). A collaboration between the Royal Tyrrell Museum and the Royal Ontario Museum, the goal of the IHS was to bring together an international slate of scientists and enthusiasts to share their research on and passion for duck-billed dinosaurs. Hosting the event at the Royal Tyrrell Museum made perfect sense to us; after all, few places in the world can boast the abundance and quality of hadrosaur fossils as are found in the classic Upper Cretaceous nonmarine strata of southern Alberta, and the Tyrrell’s collections.

Fifty-plus presentations by an international roster of dinosaur specialists and up-and-coming students rounded out two days of hardcore hadrophilia (apologies to Peter Dodson for blatantly ripping off his terminology). The IHS was also an opportunity for all of us to honor the contributions of David Weishampel (David 3).

Setting the international tone were our five keynote presenters: Rodolfo Coria (Argentina), Pascal Godefroit (Belgium), Jack Horner (U.S.A.), Khishigjav Tsogtbaatar (Mongolia), and our honored guest, David Weishampel (U.S.A.). The watershed nature of the meeting was recognized by all attendees and, collectively, we managed to overcome unanticipated obstacles such as an impending strike by Air Canada employees, which resulted in last minute rerouting of flights and late appearances by some attendees. Be it known that we truly appreciate the efforts everyone made to attend the symposium.

This volume comprises most of the content from the symposium, and more. Because we believe this volume and its contents to be a uniquely comprehensive treatment of hadrosaurs, we chose simply to call it Hadrosaurs. The scope of the volume encompasses not only the well-known hadrosaurids proper, but also Hadrosauroidea, which allows the former group to be evaluated in a broader perspective.

The volume’s 36 chapters are organized into the following six parts, followed by an afterword by Jack Horner:

Overview includes only one chapter, written by David Weishampel. David has spent a large part of his career studying dinosaurian paleobiology and, arguably, his most significant contributions are hadrosaurian. He has conducted pioneering work on hadrosaurian parental care, feeding mechanisms, functional morphology of bizarre structures, and phylogeny. In this chapter he uses data from the second edition of The Dinosauria to document patterns of research on ornithopods over the past two centuries, and uses his wisdom to surmise where researchers may be focusing in the future.

New Insights Into Hadrosaur Origins includes six chapters that document new and historical materials that shed light on the evolution and diversity of hadrosauroids before the origins of true hadrosaurids. David Norman (David 4) reviews taxa that have been implicated in the origin of Hadrosauroidea, and presents some provocative ideas about the evolution of ornithopods leading up to hadrosaurids. A standout chapter by Tsogtbataar et al. describes an exciting new taxon from the Djadokhta Formation of Mongolia, important for understanding the origin of hadrosaurids (it is rendered beautifully on the cover of the book by Julius Csotonyi). McDonald et al., You et al., and Barrett et al. provide new information about known specimens, and help sort out some long-standing questions about these specimens. Similarly, Main et al. and Larson et al. remind us of the importance of the North American hadrosauroid record for understanding the origins of Hadrosauridae.

Hadrosaurid Anatomy and Variation includes contributions by Gates, Bell, Farke and Herrero, Evans, Campione, Brink, and colleagues, and focuses on the anatomy of a variety of hadrosaurid taxa from western North America. Gates, Bell, Farke and Herrero, and colleagues describe new specimens from stratigraphic units that are rapidly proving to be important sources of new information about hadrosaur diversity and distributions, whereas the contributions by Evans, Campione, Brink, and colleagues provide in-depth descriptions and interpretations of known taxa and specimens. The morphological details provided here will lead undoubtedly to improved comparative studies.

Biogeography and Biostratigraphy documents the distribution of hadrosaurids in time and space. Here, chapters by Ramírez-Velasco et al. and Dalla Vecchia and colleagues stand out as exceptionally detailed overviews of hadrosaur occurrences in Mexico and Europe, respectively. Similarly, contributions by Bolotsky et al., Coria, and Sullivan and Lucas go a long way to help improve our understanding of hadrosaurian diversity in eastern Asia, South America, and the Southwestern U.S.A. The contribution by Tanke and Evans underscores the importance of properly documenting locality data for specimens.

Function and Growth includes seven contributions that address function, growth, and life habits. Studies of hadrosaur morphology, locomotion, and function by Maidment et al., Persons and Currie, and Henderson employ evolving techniques in computer modeling and engineering that we hope will spark discussion and renewed interest in this topic. Nabavizadeh revisits the all-important question of jaw kinetics via predentary morphology, and Guenther’s comparison of postcrania is a step toward identifying different developmental pathways in hadrosaurs. Erickson and Zelenitsky describe ontogenetic changes in tooth morphology/histology in Hypacrosaurus stebingeri that reflect dietary changes during development. Lastly, Brinkman’s size-distribution data are the basis of conclusions that challenge conventional wisdom related to growth rates in hadrosaurs.

Preservation, Tracks, and Traces is the last part of the volume and includes eight chapters, including contributions by Manning et al., Prieto-Márquez and Wagner, and Bell on skin and skin traces. Of particular note is the chapter on the origins of the classic Maiasaura bonebed by Schmitt et al., which many of us have awaited for years (no pressure anymore, Jim!). Contributions by Eberth et al. and Hone et al. present more evidence that some hadrosaurs lived in large, segregated herds, perhaps rivaling in size those of centrosaurian ceratopsians. Back in Alberta, Therrien et al. provide the first evidence of hadrosaur tracks from the Oldman Formation of Alberta, and Tanke and Rothschild provide an exhaustive survey of paleo-osteopathologies in hadrosaurs from Dinosaur Provincial Park.

Nomenclature note – Unlike most forms of science, taxonomy can be quite democratic. Over the last two decades, numerous clade names and definitions have been proposed for the hadrosaurian part of the ornithopod family tree. Rather than imposing a particular taxonomic scheme on the book’s contributors, we chose to allow contributors to employ their preferred taxonomy. Not surprisingly, the book reveals little consensus. In particular, readers may find differential use of the terms Hadrosauridae, Hadrosaurinae, and Saurolophinae across the book’s chapters a bit confusing. In order to address this, and other similar confusions, we asked authors to cite their taxonomic sources where necessary.

In summary, we have tried our best to present a group of well-balanced and consistently edited manuscripts, while allowing the authors to express their individual styles. We hope that you all enjoy the volume and find it useful for years to come.

David A. Eberth

David C. Evans