Key words: Hadrosauridae, Cretaceous, East Coast, North America, phylogeny.

Albert Prieto-Márquez amarquez@bio.fsu.edu, Department of Biological Science, Florida State University, Tallahassee, Florida, 32306-1100, U.S.A.; David B. Weishampel dweisham@mail.jhmi.edu, Center for Functional Anatomy and Evolution, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205, U.S.A.; John R. Horner jhorner@montana.edu, Museum of the Rockies, Montana State University, Bozeman, Montana 59717, U.S.A.