the event, thirty-six of which were later incorporated into a book, titled Hadrosaurs, published in 2015. The volume was brought together primarily by palaeontologists David A. Eberth and David C. Evans, and featured an afterword from John R. Horner, all of whom also contributed to one or more of the studies published therein. The first chapter of the volume was a study by David B. Weishampel about the rate of ornithopod research over history, and the interest in different aspects of it over that history, using the 2004 volume The Dinosauria as the source of data on the amount of works published in each decade. Various periods of high and low activity were found, but the twenty-first century was found to overwhelmingly be the most prolific time, with over two-hundred papers published. The advent of the internet was cited as a likely catalyst for this boom. Hadrosaur research experienced high levels of diversity within the decade, with previously uncommon subjects such as growth, phylogeny, and biogeography experiencing more attention, though the functional morphology of hadrosaurids was found to have declined in study since the Dinosaur Renaissance. Classification The family Hadrosauridae was first used by Edward Drinker Cope in 1869, then containing only Hadrosaurus. Since its creation, a major division has been recognized in the group between the hollow-crested subfamily Lambeosaurinae and the subfamily Saurolophinae, historically known as Hadrosaurinae. Both of these have been robustly supported in all recent literature. Phylogenetic analysis has increased the resolution of hadrosaurid relationships considerably, leading to the widespread usage of tribes (a taxonomic unit below subfamily) to describe the finer relationships within each group of hadrosaurids. . Lambeosaurines have also been traditionally split into Parasaurolophini and Lambeosaurini. These terms entered the formal literature in Evans and Reisz's 2007 redescription of Lambeosaurus magnicristatus. Lambeosaurini is defined as all taxa more closely related Lambeosaurus lambei than to Parasaurolophus walkeri, and Parasaurolophini as all those taxa closer to P. walkeri than to L. lambei. In recent years Tsintaosaurini and Aralosaurini have also emerged. The use of the term Hadrosaurinae was questioned in a comprehensive study of hadrosaurid relationships by Albert Prieto-Márquez in 2010. Prieto-Márquez noted that, though the name Hadrosaurinae had been used for the clade of mostly crestless hadrosaurids by nearly all previous studies, its type species, Hadrosaurus foulkii, has almost always been excluded from the clade that bears its name, in violation of the rules for